Influence Of Tire-Shreds' Aspect Ratio On Performance Of Mechanically Stabilized Retaining Walls

Influence Of Tire-Shreds' Aspect Ratio On Performance Of Mechanically Stabilized Retaining Walls | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Influence Of Tire-Shreds' Aspect Ratio On Performance Of Mechanically Stabilized Retaining Walls Michael Kazemzadeh, Matin Jalali Moghadam, Amirali Zad This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1925499/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 Aug, 2023 Read the published version in Arabian Journal for Science and Engineering → Version 1 posted You are reading this latest preprint version Abstract Reusing scrap tires to save storage space or lower traditional disposal risks is among today's environmental challenges. Current, recycled tires are considered low-cost, lightweight materials to improve soils and retaining walls, backfills, and roadbeds. The present study investigated the effect of tire shred’s aspect ratio and weight percentage on the bearing capacity and displacement of the stabilized mechanical retaining wall with multi-plate anchors under static loading. To this end, sandy soils containing tire shreds with widths of 1 and 2 cm, aspect ratios of 1, 2, 3, 4, and 5, and weight percentages of 5, 10, 15, and 20% were examined. Also, direct shear tests were conducted for determining the shear strength parameters of the mixtures. The results demonstrated that adding more tire shreds increased bearing capacity. Also, it was found that by increasing the weight percentage of tire shreds in the mixture at a constant aspect ratio, the bearing capacity of the mixture increased. At a constant aspect ratio, the horizontal wall displacement incremented by increasing the weight percentage of the tire shreds. Furthermore, the wall's bearing capacity was enhanced at a constant weight percentage by increasing the aspect ratio of tire shreds. The results of Piv analysis show that by increasing tire shreds aspect ratio, the particle strains on the slip surface will be increased. tire shreds scrap and recycled tires aspect ratio retaining wall plate anchor Particle Image Velocimetry (PIV) Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1. Introduction Currently, the volume of scrap tires increases dramatically with raising the number of vehicles. As a result, large warehouses are needed to store these tires. Regarding the lack of space required to store these tires and the danger involved in storing tires (e.g., fire and growth of vermin and insects), reuse and recycling of these tires have been considered a potential solution. Tire shreds are a group of shredded recycled tires with different shapes and sizes, usually varying between 50 and 300 mm according to ASTM ( 2008 ). Tire shreds used in the construction of embankments have the maximum aspect dimensions of 150 to 300 mm. These shreds have several applications, such as filling materials for embankments or retaining walls backfill. Among the essential properties of these materials are their low weight and low cost. Hataf and Rahimi ( 2006 ) tested the bearing capacity of sand reinforced with tire shreds with a width of 2 and 3 cm, aspect ratios of 2, 3, 4, and 5, and the shreds to sand ratios of 10, 20, 30, 40, and 50 vol.%. The authors concluded that the addition of tire shreds to the sand increases the bearing capacity ratio (BCR) from 1.17 to 3.9, depending on the content of the tire shreds and the aspect ratio. The maximum BCR is obtained in 40 vol.% and 3 × 12 cm dimensions. Also, the results showed that the BCR is incremented by increasing the tire shreds content. However, an optimal value is observed for the tire shreds content; exceeding the tire shreds increases leads to a reduction in BCR. Attom ( 2006 ) combined three different sand models with tire shreds that passed through sieve number #4 at 10, 20, 30, and 40 wt.% and performed the direct shear test on the samples to obtain the shear strength parameters of sand-containing mixes. Based on the results of Attom's study, with increasing the percentage of tire shreds, both the internal friction angle and the shear strength of sand increased. Meanwhile, an increment in the initial dry unit weight (γ dry ) of the sand and tire shreds mixture increased the shear strength. Warith and Rao ( 2006 ) performed a series of one-dimensional compression tests on four tire shreds samples and compared the results with previous studies' stress/strain curves. The results suggested that despite experiencing large axial strains, the average permeability of the tire shreds sample consistently remained two to three orders of magnitude higher than the design performance criterion of 0.01 cm/s for landfill drainage layers. Balunaini and Prezzi ( 2010 ) performed pullout experiments to investigate the interaction between ribbed-metal-strip reinforcement in mechanically stabilized earth walls with tire shreds. The studied soil was Ottawa sand, the size of the tire shreds was 9.5 mm, 50 to 100 mm, and 100 to 200 mm, and the weight percentage was 0, 12, 25, and 100 wt.%. Finally, the results indicated that the pullout capacity of ribbed metal strips embedded in tire shred–sand mixtures is much higher than that of ribbed metal strips embedded in samples prepared with only tire shreds. Also, the effect of tire shreds size on the pullout capacity of metal strips for mixtures prepared with low or high tire shreds content (12 or 100 wt.%) was negligible. Tafreshi and Norouzi ( 2012 ) combined 10 mm wide tire shreds with an aspect ratio of 3 to 5 with sand and performed bearing capacity tests on a mixture in the laboratory. According to the results, rubber reinforcement efficiency was enhanced by adding rubber content, the thickness of the rubber-reinforced soil layer, and the soil cap thickness up to the optimum values of these parameters. Mohan et al. ( 2016 ) conducted a series of pullout tests on ladder-type metal reinforcements in mechanically stabilized earth (MSE) walls reinforced with mixtures of Ottawa sand with 50–100 mm size tire shreds at different mixing ratios (0, 20, 25, and 35 wt.% of tire shreds). They concluded that the ladder-type metal reinforcement provides higher pullout resistance in tire shred-sand mixtures than in sand alone. Also, they reported that the pullout resistance increased with increasing tire shreds content up to 35% (by weight of tire shreds). Ghazavi et al. ( 2017 ) performed a study on the sand-tire shreds mixture to obtain the optimal volume of tire shreds in the mixture with sand. In this study, the size of the tire shreds was 0.2, 0.3, and 0.4 times footing width. They concluded that 10–15 vol.% is the optimum percentage of tire shreds by volume in the granular trench. They also showed that the footing bearing capacity improves by increasing the size of the tire shreds and increasing the thickness of the tire shred-mixed zone in the granular trench. Madhusudhan et al. ( 2017 ) combined 2mm rubber tire shreds with sand with 0, 10, 30, 50, and 100 wt. % of rubber tire shreds and performed permeability, compression, and uniform direct shear tests on them. According to their results, the permeability of mixtures decreases with increasing the percentage of tire shreds. Bahadori and Farzalizadeh ( 2018 ) combined tire powder and tire shreds with dimensions of 1×3 cm and 5, 10, 20, and 30 wt.% of 161 Firuzkuh sand and then conducted a series of 1 g shaking table model tests. The results indicated that tire powders and tire shreds decline pore-water pressure due to liquefaction. Also, the maximum shear modulus of reinforced soil incremented with increasing tire powder content in the mixture. Shariatmadari et al. ( 2018 ) investigated the effect of using tire shreds on stone columns. For this purpose, and to investigate the effects of the tire shreds, they performed a series of large-scale direct shear, large-scale oedometer, and constant head permeability tests. The tire shreds used in these tests consisted of 3 different sizes and an aspect ratio of 2. The large-scale direct shear box and oedometer tests demonstrated a 30% increase in the loading capacity of stone columns for 20% of tire content. However, the loading capacity of the stone column declined for tire mixing ratios greater than 20%. Madhusudhan et al. ( 2018 ) performed dynamic simple shear tests on a mixture of sand and tire shreds with dimensions of 2 mm and 10, 30, and 50 wt.% and compared the test results with those of cyclic triaxial tests. They concluded that the cyclic triaxial tests overestimated the shear moduli, but the damping ratios were comparable to those obtained from dynamic simple shear testing. Xiao et al. ( 2019 ) performed thermal conductivity tests on a mixture of sand and tire shreds with dimensions from 0.25 to 4 mm and volume percentages of 0, 10, 20, 30, and 40. They concluded that using tire shreds with a larger relative size ratio yields higher thermal conductivity. Also, in this study, the maximum variation in the thermal conductivity percentage difference with the relative size ratio reached about 20% at a volumetric mixing ratio of 40%. Madhusudhan et al. ( 2019 ) performed a series of conventional triaxial shear tests, direct shear tests, and dynamic triaxial tests on sand-tire shreds mixture with 0, 10, 30, 50, and 100 wt.%. The maximum size of the tire shreds was 2 mm. They concluded that increasing the percentage of tire shreds reduces the internal friction angle. Also, the effect of confining stress and the shearing rate on the angle of internal friction is negligible. Khan et al. ( 2020 ) combined sand and tire shreds with dimensions of 50, 75, and 100 mm and 0, 20, 30, and 40 wt.%. They performed modified proctor compaction tests, large-scale direct shear tests, and pullout tests. According to their results, the internal friction angle (φ) for sand-tire shreds mixture (30:70) with 100 mm tire shreds size was 38.5° and for the sand-only mixture (100:0) was 30.9°. This difference is because the tire shreds are randomly distributed in the shear zone and therefore have a higher slip resistance. Table 1 provides a summary of past research on recycled tires. Table 1 A set of tests performed on recycled tires and their results Author (s) Type of recycled tire Test Aspect ratio/Dimension Reported findings Edinçliler and Ayhan ( 2010 ) Tire Crumb & Tire Buffings Standard direct shear test & large-scale direct shear tests Tire crumb with a size of 1 to 3 mm, Tire Buffings with a size between sieves#4(4.75mm) and #10 (2mm) Three factors significantly affecting the shear strength values were normal stress, aspect ratio, and tire waste content. Also, increasing the aspect ratio of the fibers increases the shear strength of the mixture. Edinçliler et al. ( 2010 ) Tire crumb Large-scale direct shear tests 1 to 3 mm Sand-tire mixtures have higher shear strength than the sand alone. The shear strength parameters depend on the processing conditions of used tires. Three factors significantly affect the mechanical properties: normal stress, processing techniques, and the used tire content. Ayothiraman and Soumya ( 2011 ) Tire Chips Triaxial tests (UU & CD)-Load-displacement response 10 mm Mixtures of 60%T + 40%S and 40%T + 60S have the load-carrying capacity of a stone column with only stone aggregates (100S). This result demonstrates that waste tire chips can be used to partially replace stone aggregates up to about 60% in stone columns. Edincliler et al. ( 2012 ) Tire Crumb & Tire Buffings Triaxial tests Tire crumbs with an aspect ratio of 1 to 1.5. Tire buffings with an aspect ratio of 3.5 to 4 The NN-based constitutive model is observed to be very close to actual experimental results. The proposed NN models are also expressed as simple mathematical functions for practical use. Edincliler et al. ( 2013 ) Tire Crumb & Tire Buffings Cyclic triaxial tests Tire buffings with an aspect ratio of 1.5 The greater the proportion of waste tire crumbs or tire buffings on the sand, the greater is the damping ratio, the less is the shear modulus, regardless of confining pressure. Li et al. ( 2016 ) Tire crumb Resonant column tests and cyclic triaxial tests 0.18 to 0.25 mm and 0.6 to 0.85 mm The mix ratio affects the dynamic shear modulus significantly and the liquefaction susceptibility. Brara et al. ( 2017 ) Tire Rubber Modified triaxial cell test with bender elements 0.06 to 0.60 mm The shear modulus decreases with increasing rubber volume fractions for all confining pressures, while the damping ratio increases linearly. Wang et al. ( 2017 ) Tire Shred Resonant column tests D 50 : 1.52 mm The increase in shear strain reduces the maximum dynamic shear modulus but raises the damping ratio of the sand-rubber mixtures. As the dynamic shear modulus of the mixtures increments, the damping ratio declines with an increase in confining pressure. Mazumder et al. ( 2018 ) Tire Chips Large-scale direct shear tests 10 mm × 10 mm The ordinary stone columns made of stone aggregates can be replaced by encased stone columns made of 100% tire chips. Kaushik et al. ( 2018 ) Tire Chips Hydraulic conductivity tests Aspect ratio: 1 to 4 The combination of the TS1 size tire chips with gravel in the mixing ratio of 1:3 outperformed the other mixes. The hydraulic conductivity reduction was comparatively lower even on higher stress levels. Moghadam et al. ( 2018 ) Tire crumb Reduced scale model tests to investigate the behavior of MSE walls subjected to static loading Passing through sieve #4 (4.75 mm) and remaining on sieve #6 (3.35 mm) The circular anchor plates almost continually provided a higher bearing capacity and wall stability than the square plates. Moreover, the backfill with 15 wt.% RCR provided the maximum bearing capacity of the wall. Boominathan and Banerjee ( 2019 ) Tire Shred Monotonic direct shear tests, one-dimensional compression, permeability tests 2 mm Intriguingly, the permeability of the mixtures reduces with an increase in rubber content. The contact angles of sand-water and the rubber-water interfaces determined using a Goniometer explain this behavior. Bahadori and Khalili ( 2019 ) Tire powders 1-g shaking table tests D 30 of Tire Powders: 0.41 mm In all cases, the increase in frequency in the same cycles built up the shear modulus and the damping ratio. Also, with increasing shear strain, the shear modulus of the mixture decreased, but the damping ratio incremented. Sarajpoor et al. ( 2020 ) Tire crumb Hollow cylinder test D 50 : 0.83, 2.33, 6 mm Dynamic properties of sand-crumb rubber mixtures were mainly influenced by rubber content and confining stress values. In this process, relative density and rubber particle size were less effective in this regard. Moussa and El Naggar ( 2021 ) TDA Cyclic triaxial test 9.53 to38.1 mm The shear modulus decreases with increasing shear strain amplitudes. Also, it has a similar trend to natural granular soils. El Naggar and Iranikhah ( 2021 ) TDA Large-scale direct shear 30–40 mm, 40–50 mm,50–60 mm, 60–70 mm, and 70–75 mm. The addition of TDA to the considered soils significantly reduces the dry unit weight, making the mixtures attractive for applications requiring lightweight fill materials. El Naggar and Zahran ( 2021 ) TDA Large-scale triaxial tests D max of 19.05, 25.4, 38.1, 50.8, and 76.2 The shear strength of TDA builds up by incrementing the maximum particle size, while the cohesion did not have a specific trend. Moreover, the samples exhibited a rise in the secant elastic modulus by increasing the particle size El Naggar et al. ( 2021 ) TDA Large-scale direct shear tests 9.5–101.6 mm The angle of internal friction (φ) rose with increasing the maximum particle size. Moreover, the secant shear modulus also exhibited an increase by increasing the maximum particle size. For the first time, Moghadam et al. ( 2018 ) used plate anchors vertically in the retaining walls. In this research, the effect of adding recycled crumb rubber in the backfill of the mechanically stabilized earth wall with plate anchors with different characteristics was investigated. The results of this study showed that larger plate anchors had more bearing capacity and with increasing the amount of recycled crumb rubber, the horizontal displacement of the wall decreases. Moghadam et al. ( 2019 ) conducted experimental modeling to study the effect of using vertical plate anchors with different shapes & configurations in mechanical stabilized earth walls. Results of this research indicated that circular plate anchors had the most bearing capacity and using a diamond reinforcement configuration provides more bearing capacity than a square reinforcement configuration. The present paper considers the experimental tests on the bearing capacity of mechanically stabilized walls reinforced by plate anchors, where the backfill material is a mixture of soil and tire shreds which was not subject to study till now. The factors evaluated for this purpose include changes in weight percentage and aspect ratio of tire shreds on the bearing capacity of the wall, deformations and horizontal displacements of the wall, and the formation of critical slip surfaces or wedge rupture. Also, the particle image velocimetry (PIV) technique was employed to observe the slip surfaces formed in the retaining wall backfill. 2. Experimental Tests Experiments were performed on a laboratory scale using a 1: 10 scale. Based on this scale, the length, width, and height of the retaining wall were scaled from 7 × 5 × 5 m to 70 × 50 × 50 cm. The face of permanent retaining walls was built using prefabricated or integrated concreted concrete panels. Like the study of Moghadam et al., ( 2018 ), the face of the retaining wall was manufactured using an aluminum sheet with a thickness of 0.9 mm (equivalent to a 30-cm concrete face) based on the recommendation by Wood ( 2017 ). A chamber with a length of 124 cm, a width of 53 cm, and a depth of 82 cm was manufactured to build the retaining walls. The purpose of increasing the length and depth of the chamber is to prevent boundary effects. To observe the soil's failure wedge, tempered glass with a thickness of 30 mm was used on one side of the chamber. This thickness of tempered glass was chosen to ensure that it did not deform and bulge during loading. Also, 20 cm of soil was placed under the wall as an earthen bed. Figure 1 illustrates a schematic of the test chamber, loading system, load cell, strain gauges, and loading heel. The soil used in all experiments was dry sand from the Soufian region of East Azerbaijan province, which was classified as poorly graded sand (SP) according to the Unified Soil Classification System (USCS). The soil properties are displayed in Table 2 . Table 2 soil properties ϕ (°) Υ dmin (kN/m 3 ) Υ dmax (kN/m 3 ) G s e min e max D 60 (mm) D 50 (mm) D 30 (mm) D 10 (mm) C c C u 28 14.2 16.76 2.64 0.54 0.82 0.3 0.28 0.24 0.22 0.87 1.36 Plane strain conditions were established using a loading heel with a length of 50 cm, a width of 10 cm, and a height of 3 cm (The loading heel is equivalent to the strip footing.). The friction between the lower part of the loading heel and the soil was reduced by thoroughly polishing all parts of the loading heel. The length of the anchor rod used in this research is 50 cm, which is equivalent to a 5-m anchor rod by applying a scale factor of 1:10. The diameter of the anchor rod is 4 mm, which was equivalent to 4 cm in diameter rebar. Using the results of Moghadam et al., ( 2018 ), the arrangement of anchors was selected as a diamond (Fig. 2 ). The reason for choosing this configuration is that they showed the superiority of the diamond arrangement to other ones (square and even 5-anchor) in terms of higher bearing capacity and lower horizontal displacement. The center-to-center distance of the anchors in the horizontal and vertical directions was considered 30 cm. Furthermore, using the results of Moghadam et al., ( 2018 ), the shape of the anchor plates was chosen as a square. The square plates had dimensions of 2.6 cm and a thickness of 3 mm (Fig. 3 ). Three-plate square reinforcements with a 12- cm center-to-center distance were considered in This configuration (Fig. 4 ). The tire shreds used were all free of yarn and metal. In all tests, the tires’ thickness was 2 mm, widths of 2 and 1 cm, and aspect ratios of 1, 2, 3, 4, and 5 (Fig. 4 ). These tire shreds were mixed with Soufian sand soil at 5, 10, 15, and 20 wt.% and used as backfill material for the retaining wall. Table 3 presents the specifications of the tire shreds, including their aspect ratio. Figure 5 shows the photos of tire shreds for experimental tests. Table 3 Dimensions of the tire shreds in the Fig. 4 Row ID in Fig. 4 Dimensions (cm) Weight percentages (%) 1 a 1*1 5, 10, 15, 20 2 b 1*2 5, 10, 15, 20 3 c 1*3 5, 10, 15, 20 4 d 1*4 5, 10, 15, 20 5 e 1*5 5, 10, 15, 20 6 f 2*2 5, 10, 15, 20 7 g 2*4 5, 10, 15, 20 8 h 2*6 5, 10, 15, 20 9 i 2*8 5, 10, 15, 20 10 j 2*10 5, 10, 15, 20 3. Method Of Experiments Firstly, for determining the strength parameters of sand-tire shred mixtures, standard direct shear tests were conducted based on ASTM ( 2011 ) on sand-tire shred mixtures. For this purpose, the authors used a large-scale direct shear apparatus with a dimension of 30 * 30cm. Second, The effects of tire shreds’ weight percentage and aspect ratio were investigated by performing 41 tests. In all tests, the unit weight of sand was 15.36 kN/m3, i.e., a relative density of 50%. At first, the Sufian sand soil and tire shreds were mixed. Then, the sand precipitation method was performed to reach the desired relative density. The applied load was measured by a 2-ton load cell and captured via a data logger connected to the laptop. All tests were performed under constant strain conditions with six steps of 5 mm to achieve the highest possible loading rate accuracy. All experiments were performed in 7 stages, the first stage was load-free, and only the first photo of the wall surface was taken. The settlement related to the applied load was controlled using a strain gauge. Also, the horizontal wall displacement was measured using three strain gauges installed on the wall face. The first strain gauge was installed at a distance of 3 cm from the edge of the face, the second strain gauge at a distance of 15 cm from the first one, and the third strain gauge at a distance of 15 cm from the second one. A view of the test chamber and its components are shown in Fig. 6 . 4. Experimental Test Results 4.1. Direct shear tests results The results of the direct shear tests are presented in Table. 4. Based on obtained results, it was revealed that for all tire shreds with a width of 1 and 2cm in a constant weight percentage in tire shred-sand mixtures, both the internal friction angle and cohesion of the mixture will be incremented. It means that the maximum internal friction angle and cohesion of mixtures were belongs to mixtures consisting of tire shreds with an aspect ratio of 5 (1*5 and 2*10). Also, the results show that in a constant aspect ratio of tire shreds, increasing tire shreds weight percentage in mixtures will increase the internal friction angle and cohesion of the mixtures. The maximum internal friction angle and cohesion of the sand-tire shred mixtures belong to mixtures with 20% content of tire shreds. Table 4 results of direct shear tests Row Tire shred's dimension Tire shred's content c(kPa) Φ (degree) Row Tire shred's dimension Tire shred's content c(kPa) Φ (degree) 1 1*1 5 2.2 28.2 21 2*2 5 12.5 35.1 2 1*1 10 4.8 29.1 22 2*2 10 12.7 35.4 3 1*1 15 8.8 30.4 23 2*2 15 23.6 36.4 4 1*1 20 15.9 32.5 24 2*2 20 25.1 38.1 5 1*2 5 3.6 28.8 25 2*4 5 12.6 35.2 6 1*2 10 14.9 30.9 26 2*4 10 18.2 36.3 7 1*2 15 18.8 33.1 27 2*4 15 25.2 38.8 8 1*2 20 20.4 35.6 28 2*4 20 30.5 41.3 9 1*3 5 4.5 29 29 2*6 5 22.7 37.6 10 1*3 10 18.6 31 30 2*6 10 28.1 40.9 11 1*3 15 23.6 33.7 31 2*6 15 30.5 41.2 12 1*3 20 25.6 37.9 32 2*6 20 32.1 42.5 13 1*4 5 14.5 31.6 33 2*8 5 24.7 38.5 14 1*4 10 18.7 32.1 34 2*8 10 29.6 41 15 1*4 15 25.8 34.5 35 2*8 15 32.6 42.4 16 1*4 20 32.5 38.3 36 2*8 20 34.5 42.9 17 1*5 5 23.6 34.9 37 2*10 5 25.1 39.8 18 1*5 10 24.5 35.7 38 2*10 10 30.1 41.6 19 1*5 15 28.2 36.8 39 2*10 15 34.2 42.2 20 1*5 20 33.1 38.8 40 2*10 20 35.4 43.9 4.2. Bearing capacity evaluation The mixes containing 5% of tire shreds with a width of 2 cm revealed that the highest bearing capacity (i.e., 58 kPa) was obtained from tire shreds with 2×10 cm dimensions (Fig. 7 a). The wall, backfilled with mixes of tire shreds and sands with dimensions of 2×8, 2×6, 2×4, and 2×2 cm was, reached the bearing capacity of 53.5, 51.3, 32.1, and 30.6 kPa, respectively. Analyzing the load-bearing capacity of the mixes containing 5% tire shreds with 1 cm width demonstrated that tire shreds with dimensions of 1×5 were shown the maximum load-bearing capacity (44 kPa) of the wall, among others. The mixes containing tire shreds with dimensions of 1×4, 1×3, 1×2, and 1×1 cm were in the next rank in terms of the bearing capacity (i.e., 30.5, 24.5, 19.6, and 16.6 kPa, accordingly). Comparing the results of bearing capacity obtained from the mixes containing 5% of tire shreds indicates that the tire shreds with dimensions of 1×5 cm had a higher bearing capacity compared to tire shreds with dimensions of 2×4 & 2×2 In addition, the optimum dimensions in terms of the amount of loading in the constant settlement applied in the experimental tests in 5% of tire shreds were 2×10 and 2×8 cm, respectively. According to Fig. 7 (a) (mixed with 5% of tire shreds with a width of 1 cm), raising the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5 will lead to an increase in bearing capacity by 18%, 25%, 24.4%, and 44.2%, respectively. Based on Fig. 7 (b), for mixed with 5% of tire shreds with a width of 2 cm, as the aspect ratio increases from 1 to 2, 2 to 3, 3 to 4 m, and 4 to 5, the bearing capacity of the wall will increase by 1.3%, 59.8%, 4.3%, and 8.4% respectively. The results of tests performed with 10 wt.% of tire shreds with a width of 1 cm are presented in Fig. 7 (c). As can be seen, the most considerable bearing is related to the test performed with 1×5- cm tire shreds. In this test, the load recorded on the wall backfill was 46.2 kPa. Finally, the mixes containing tire shreds with dimensions of 1×4, 1×3, 1×2, and 1×1 had bearing capacities of 35.3, 34.3, 25.4, and 24.7 kPa, respectively. Also, according to results presented in Fig. 7 (d), the mixes containing 10 wt.% of tire shreds with a width of 1 cm showed that mixes with 2×10 cm tires had the highest bearing capacity (i.e., 84.1 kPa) among the tire shreds with a width of 2 cm and 10 wt.%. In the next rank, the mixes containing tire shreds with dimensions of 2×8, 2×6, 2×4, and 2×2 cm had a bearing capacity of 80.2, 75.7, 38.1, and 32.3 kPa, accordingly. Comparing the results obtained from the tests performed on a mix with a 10 wt.% of tire shreds and a width of 1 and 2 cm showed that the tire shreds with dimensions of 1×5 cm compared to the tire shreds with dimensions of 2×4 and 2×2 cm had higher bearing capacities. In addition, tire shreds with dimensions of 1×4 and 1×3 had better bearing capacity at 10 wt.% than tire shreds with dimensions of 2×2 cm. In the tests performed at 10 wt.%, the best and highest bearing capacities were related to tire shreds with dimensions of 2×10 and 2×8 with bearing capacities of 84.1 and 80.2 kPa, respectively. Analysis of the results obtained from tests performed with 1-cm width tire shreds reveals that at 10 wt.%, with raising the aspect ratio raises from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, wall bearing capacity elevated by 2.8%, 35%, 2.9%, and 30.9%, accordingly. In mixes containing 10 wt.% of tire shreds and a width of 2 cm, with increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and from 4 to 5, wall bearing capacity incremented by 18%, 98.7%, 5.9%, and 4.8% respectively. The results of tests performed with 15 wt. % of the tire shreds (Fig. 7 (e) show that in the tests with 1-cm width of tire shred, the highest bearing capacity was related to the tire shreds with dimensions of 1×5 cm and bearing capacity of 71.5 kPa. In the next rank, the mixes containing tire shreds with dimensions of 1×4, 1×3, 1×2, and 1×1 recorded 49.4, 43.5, 35.5, and 25.3 kPa bearing capacities, respectively. The test performed with 15 wt.% of tire shreds with 2×10 cm dimensions indicated that tire shreds with 15 wt.% and 2×10 cm dimensions had a higher bearing capacity than the other tire shreds with a width of 2 cm. The results revealed that the mixture of sand and 2×10 cm tire shreds was loaded by 120.2 kPa at 15 wt.%. According to results shown in Fig. 7 (f), mixtures containing tire shreds with dimensions of 2×8, 2×6, 2×4, and 2×2 had bearing capacities of 88.9, 83.4, 64.7, and 49.2 kPa, respectively. Comparing the results obtained for tire shreds with a width of 1 and 2 cm at a weight of 15% exhibited that the soil reinforced with 1×5 cm tire shreds had a higher bearing capacity than the soil reinforced with 2×4 and 2×2 cm tire shreds. Also, sand soil reinforced with 1×4 cm tire shreds had a slight bearing capacity difference with sandy soil reinforced with 2×2 cm tire shreds. The highest bearing capacity in the mentioned tests for the weight percentage of 15% of tire shreds was related to the soil reinforced with 2×10 cm tire shreds with a bearing capacity of 120.2 kPa. On the other hand, the lowest bearing capacity was related to the soil reinforced with 1×1 cm tire shreds with a bearing capacity of 25.3 kPa. In mixes containing 15 wt.% of tire shreds and a width of 1 cm, with increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, wall bearing capacity increased by 40.3%, 22.5%, 13.6%, and 44.7%, respectively. Also, in mixes containing 15 wt.% of tire shreds and a width of 2 cm, with increasing the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the bearing capacity of the wall incremented by 31.5%, 28.9%, 1.8%, and 41.6%, accordingly. The results obtained from tests performed with tire shreds with a width of 1 cm at 20 wt.% are shown in Fig. 7 (g). Among the tire shreds with a width of 1 cm at 20 wt.%, those with dimensions of 1×5 cm had a better bearing capacity (i.e., 83.3 kPa) than the tire shreds with a width of 1 cm. In the next rank, the tire shreds with dimensions of 1×4, 1×3, 1 ×2, and 1×1 cm had bearing capacities of 76.5, 56.8, 38.2, and 33.3 kPa, respectively. Also, according to Fig. 7 (h) results, mixes containing 20 wt.% of tire shreds with a width of 2 cm show that tire shreds with dimensions of 2×10 cm and a bearing capacity of 156.5 kPa had the highest bearing capacity among tire shreds with a width of 2 cm. Next, tire shreds with dimensions of 2×8, 2×6, 2×4, and 2×2 cm and bearing capacity of 151.1, 111.4, 87.4, and 52.5 kPa, respectively, were placed in the following ranks compared to tire shreds with dimensions of 2×10 cm. In the mixes containing soil and 20 wt.% of the tire shreds, the mixes containing tire shreds with dimensions of 1×5, 1×4, and 1×3 cm had higher bearing capacity than the tire shreds with dimensions of 2×2 cm. The highest bearing capacity in the mixtures of soil and 20 wt.% of tire shreds was related to the mixture of soil and tire shreds with dimensions of 2×10 cm and a bearing capacity of 156.5 kPa. Also, as in the previous results, the lowest bearing capacity was related to the mixture of soil and 1×1 cm tire shred. Soil mixes containing 20 wt.% of tire shreds and a width of 1 cm indicate that by raising the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the bearing capacity of the wall incremented by 14.7%, 48.7%, 34.7%, and 8.9%, respectively. In mixes containing 20 wt.% of tire shreds with a width of 2 cm, with increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the wall bearing capacity increased by 66.5%, 27.5%, 35.6%, and 3.3% accordingly. The study of the obtained bearing capacity shows that by increasing the aspect ratio of the tire shreds at a constant weight percentage (increasing the dimensions), the bearing capacity of the mixture increased. Also, with the constant dimensions and aspect ratio of tire shreds, increasing the weight percentage of tire shreds from 5 to 20 leads to a high bearing capacity of mixtures. The performed test on the retaining wall with virgin soil that has no content of tire shreds showed that the wall had a bearing capacity of 14.8 kPa. Comparing this to the results obtained from tests performed by mixtures of sand-tire shred reveal that adding tire shreds in the backfill of a retaining wall had a positive effect on the bearing capacity of the wall. Also, it was concluded that for tire shred with a width of 2cm increasing tire shred’s weight percentage from 0 to 5 in mixtures with sand, the increment in bearing capacity was more significant than for tire shred with a width of 1cm in same weight percentage. The increase in bearing capacity of the mixtures of sand-tire shreds can be related to the interlocking between sand particles and tire shreds. Increasing tire shreds’ aspect ratio or weight percentage in mixes will help to strengthen the interlocking between sand particles and tire shreds and that results in an increment in the bearing capacity of walls. 4.3. Retaining wall`s stabilization The results of laboratory tests regarding the horizontal wall displacement are presented in Fig. 8 . As shown in Fig. 8 (a), the minimum wall horizontal displacement (i.e., 10.7 mm) against the applied settlement occurred in a mix containing 5 wt.% of tire shreds with a width of 1 cm and shreds dimensions of 1×1 cm. In the next rank, mixes containing 5% tire shreds with dimensions of 1×2, 1×4, 1×3, and 1×5 cm had horizontal displacements of 10.8, 10.9, 11.2, and 11.8 mm, respectively. Based on the results presented in Fig. 8 (b) for the mixes containing 5 wt.% of tire shreds with a width of 2 cm, the lowest horizontal wall displacement (i.e., 10.8 mm) was obtained for a mixture of sand and tire shreds with dimensions of 2×2 cm. In the next rank, the mixes containing tire shreds with dimensions of 2×4, 2×6, 2×8, and 2×10 had horizontal displacements of 11.1, 11.3, 11.5, and 11.9 mm, correspondingly. Comparing the results obtained for tests performed with a mix with 5 wt.% of tire shreds and a width of 1 and 2 cm shows that the lowest horizontal wall displacement (10.7 mm) occurred in mix-tire shreds with dimensions of 1×1 cm. Among all tests performed with a 5 wt.% mixture of tire shreds, the test performed with tire shreds with dimensions of 1×5 and 2×10 cm had the highest horizontal wall displacement of 11.8 and 11.9 mm, respectively. For mixes containing 5 wt.% of sand soil and tire shreds with a width of 1 cm, by increasing the ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, horizontal wall displacement increased by 0.9%, 0.9%, 2.7%, and 5.3% accordingly. For mixes with 5 wt.% of sand and tire shreds with a width of 2 cm, as the aspect ratio of tire shreds increased from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, horizontal wall displacement increased by 2.7%, 1.8%, 1.7%, and 3.4% respectively. As presented in Fig. 8 (c), the test performed with a mixture of sand and tire shreds with dimensions of 1×1 cm and 10 wt.% had the lowest horizontal wall displacement of 10.8 mm among laboratory modeling performed with tire shreds with a width of 1 cm and 10% weight percentage. The results also revealed that by increasing the dimensions and aspect ratio of tire shreds with a width of 1 cm, the horizontal wall displacement built up by 11.4, 11.5, 12, and 12.3 mm for tests performed with tire shreds with dimensions of 1×2, 1×3, 1×4, and 1×5, correspondingly. Among the tests performed on mixes containing sand and tire shreds with a width of 2 cm at 10 wt.%, tire shreds with dimensions of 2×2 cm and a horizontal wall displacement of 11 mm had the lowest horizontal displacement. In the next rank, the mixes containing tire shreds with dimensions of 2×4, 2×6, 2×8, and 2×10 cm indicated horizontal wall displacements of 11.5, 11.6, 12.1, and 12.4 mm, respectively. These results are shown in Fig. 8 (d). Comparing Fig. 8 (c) & Fig. 8 (d) for the mixes containing 10 wt.% of tire shreds with widths of 1 and 2 cm shows that the lowest horizontal wall displacement (10.8 m) occurred in a mix with tire shreds dimensions of 1×1 cm. On the other hand, the highest horizontal wall displacement (12.4 mm) occurred in the mix with tire shreds with dimensions of 2×10 cm. According to horizontal displacement results of the wall versus the aspect of loading heel settlement, in a mix containing 10 wt.% of soil and tire shreds with dimensions of 1 cm, increasing the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacement increased by 5.5%, 0.9%, 4.3%, and 2.5%, correspondingly. Mixes containing 10 wt.% of sand and tire shreds with dimensions of 2 cm show that by increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacements were incremented by 4.5%, 0.9%, 4.3%, and 2.5%, respectively. According to Fig. 8 (e), among the mixes containing 15 wt.% of tire shreds with a width of 1 cm, the lowest horizontal wall displacement was related to the test performed with a mixture of tire shreds with dimensions of 1×1 cm. In the above test, the horizontal wall displacement was 11.3 mm, i.e., the lowest among the mixes containing tire shreds with a width of 1 cm. After that, the mixes containing tire shreds with dimensions of 1×2, 1×3, 1×4, and 1×5 and horizontal wall displacement of 11.8, 12.1, 12.4, and 12.5 mm were placed in the following ranks. Analyzing the results of the mixes containing 15 wt.% of tire shreds with a width of 2 cm which was shown in Fig. 8 (f) demonstrated that the lowest horizontal wall displacement (12 mm) was related to the test performed with tire shreds with dimensions of 2×2 cm. Here, the mixtures with tire shreds with dimensions of 2×4, 2×6, 2×8, and 2×10 and horizontal wall displacement of 12.1, 12.3, 12.4, and 12.8 mm, respectively, were placed in the next ranks. Comparing the results of tire shreds with a width of 1 and 2 cm in mixtures with 15 wt.% of the tire shreds revealed that the lowest horizontal wall displacement (11.3 mm) was related to the test performed with a mixture of sand and tire shreds with dimensions of 1×1 cm. Meanwhile, the highest horizontal wall displacement (12.8 mm) was related to the test performed with tire shreds with dimensions of 2×10 cm. With increasing the aspect ratio of mixtures of 15 wt.% tire shreds with a width of 1 cm from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacement increased by 4.4%, 2.5%, 1.7%, and 1.6%, respectively. The test results for mixtures with 15 wt.% tire shreds with a width of 2 cm show that by increasing the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacement increased by 0.9%, 1.6%, 0.8%, and 3.2%, respectively. The mixes containing 20 wt.% of tire shreds and a width of 1 cm (Fig. 8 (g)) reveal a mixture of sandy soil and tire shreds with dimensions of 1×1 cm and a width of 1 cm had the lowest horizontal wall displacement (12 mm). In the next rank, the mixtures with tire shreds with dimensions of 1×2, 1×3, 1×4, and 1×5 had horizontal wall displacements of 12.4, 12.5, 12.6, and 12.8 mm, respectively. The mixes with tire shreds with dimensions of 2×2 cm (Fig. 8 (h) had the lowest horizontal wall displacement (12.2 mm) in the tire shreds with a width of 2 cm. In the next rank, tire shreds with dimensions of 2×4, 2×6, 2×8, and 2×10 had horizontal wall displacements of 12.6, 12.7, 13, and 14.2 mm, respectively. Comparing the results of all tests performed with mixtures of soil and 20 wt.% of tire shreds shows the lowest horizontal wall displacement (12 and 12.2 mm) occurred in the mixes with tire shreds of 1×1 and 2×2 cm, respectively. On the other hand, the highest horizontal wall displacement (14.2 mm) occurred in the mixes with tire shreds with dimensions of 2×10 cm. The mix containing 20 wt.% of tire shreds with a width of 1 cm and sand soil indicates that by increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacements raised by 3.3%, 0.8%, and 0.8%, and 1.6%, respectively. Also, mixes containing 20 wt.% of tire shreds with a width of 2 cm and sand soil show that by increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacement increased by 3.3%, 0.8%, 2.4%, and 9.2%, respectively. The results show that the horizontal displacement of the retaining wall made from virgin soil without any tire shreds’ content was 16.3 mm. Comparing this outcome to those obtained from tests conducted on sand-tire shred mixtures indicated that adding tire shreds to the backfill of the wall will result in a decrease in horizontal wall displacement. A significant decrease in the wall’s horizontal displacement was seen by increasing the tire shreds content from 0 to 5% wt in both cases in which the tire shreds dimension was 2×2 & 1×1. Also, the results show that by increasing tire shreds’ content or tire shreds’ aspect ratio the horizontal displacement of the retaining wall will be increased. 4.4. Scrap tires vs. Slip surfaces The slip surfaces formed in the embankment were investigated using the particle image velocimetry (PIV) technique (White et al., 2003 ). Figure 9 shows the results of PIV analysis and processing for tests performed with tire shreds with a width of 1 cm. Also, The strain range of soil particles is shown on the right side of the figure. These results are displayed based on the weight percentage and dimensions of the tire shreds. The results of PIV analysis for tests performed with tire shreds with dimensions of 1×1 cm at different weight percentages evidenced that by increasing the weight percentage of tire shreds with dimensions of 1×1 cm in the mixture of sand and tire shreds the strain gradually increased. In tests performed with tire shreds with dimensions of 1×2 and 1×3 cm, similar to tire shreds with dimensions of 1×1, as the weight percentage of tire shreds increases, strain built up on the slip surface will be incremented. Analysis of PIV results for tests performed with tire shreds with dimensions of 1×4 cm indicated that in mixes containing 5 wt.% of tire shreds and having dimensions of 1×4 cm, a wedge with a low strain rate was formed. Next, with increasing the weight percentage of the tire shred, the strain gradually increased and expanded. In mixes containing 5 wt.% of tire shreds with dimensions of 1×5 cm, a wedge failure was formed with a low strain rate. Next, the strain under the loaded area increased as the tire shreds content was built up to 10 wt.%. Afterward, by increasing the weight percentage to 15%, the strains augmented again. Finally, by increasing the weight percentage of tire shreds with dimensions of 1× 5 cm to 20%, the strains reached their maximum value at the slip surface. The PIV analysis results for the mixes containing tire shreds with dimensions of 2×2 cm (Fig. 10 ) showed that by increasing the tire shreds content, the stress concentration reached its highest level in the mixture of soil and 20 wt.% of tire shreds with dimensions of 2×2 cm. In mixes containing 5 wt.% of tire shreds, the wedge was formed with a small strain below the loading area. Next, with increasing the tire shreds content with dimensions of 2×4 cm from 5 to 10 wt.%, the range of strains increased slightly. Increasing the weight percentage of tire shreds with dimensions of 2×4 cm to 15% increased the strains. Finally, by increasing the weight percentage of tire shreds with dimensions of 2×4 cm to 20 wt.%, again the strains were increased. Like the trends that occurred in past experiments, by increasing tire shreds’ content for tire shreds with a dimension of 2×6, 2×8, & 2×10, the strains at the slip surface will be increased. Figure 11 shows the Piv analysis results for the retaining wall made with virgin soil. The comparison shows that the strains formed at the slip surface of the retaining wall made with virgin soil and without any tire shred content were much more than those retaining walls made with mixes of tire shred and sand. A significant decrease in strains at the slip surface was seen by adding 5% wt tire shreds to the backfill of retaining walls. The depth of failure wedge was the same for all the tests, approximately. It means that adding tire shreds had not any significant effect on the depth of failure wedge in comparison with virgin soil. Also, It should be mentioned that the distance between the crown of the wall and the slip surface was identical in all tests, and tire shreds did not affect this parameter, too. From the results of the PIV analysis, it can be concluded that by increasing the aspect ratio of tire shreds with a width of 1 cm from 1 to 2, at all weight percentages, an increase in strains on the slip surface will be seen. From Piv analysis, in tire shreds with a width of 1 cm, it was indicated that by increasing tire shreds aspect ratio the strains at slip surface will be incremented. This trend was also seen for tire shreds with a width of 2 cm. Comparing the PIV results for tests conducted on mixes with different tire shreds and horizontal wall displacement against the settlement induced below the wall shows that with increasing the tire shreds content of the mixes, the generated strains increase gradually. The maximum strain created in the slip surface occurred in a mix containing 20 wt.% of soil and tire shreds with dimensions of 2×10 cm. Analysis of the PIV results also confirmed this finding. A comparison of PIV analysis and horizontal displacement results shown in Fig. 7 also confirmed the agreement between PIV and horizontal wall displacement. 5. Conclusion In this paper, the results of laboratory modeling are presented to investigate the effect of the aspect ratio and weight percentage of tire shreds on the embankment of retaining walls stabilized with multi-plate restraints. The particle image velocimetry (PIV) technique observed the wedge failure and evaluated the slip surface. The results are as follows: 1. Resluts of direct shear tests show that internal friction angle and cohesion of the sand-tire shred mixtures will be incremented by increasing tire shreds aspect ratio in a constant weight percentage. Also, by increasing the tire shred's weight percentage in a constant aspect ratio, the cohesion and internal friction angle of the sand-tire shred mixtures will be increased. It can be concluded that adding tire shreds with studied dimensions and weight percentages to sand improved the shear strength parameters of sand. 2. Increasing the weight percentage of tire shreds from 5% to higher percentages leads to increasing the load-bearing capacity of the retaining wall. The highest load-bearing capacity was related to the embankment with a mixture of 20 wt.% of tire shreds with dimensions of 2×10 cm. At a constant weight percentage, increasing the aspect ratio of tire shreds in the mixture enhanced the load-bearing capacity of the wall. These were due to an increment in internal friction angle and cohesion of the sand-tire shred mixtures used as a replacement for the backfill virgin sandy soil in this study. 3. In all tests and at a constant aspect ratio and dimensions, the horizontal wall displacement increased by incrementing the weight percentage of the tire shreds. Also, it was concluded that by increasing the tire shreds aspect ratio in a constant weight percentage, the horizontal displacement of the wall will be increased. 4. The Piv analysis results show that by increasing tire shreds content in a constant aspect ratio, the strains at the slip surface would be incremented. It was found that the strains were increased at slip surface by increasing tire shreds aspect ratio in a constant weight percentage. 5. Results reveal that using tire shreds in the backfill of the retaining wall provides more bearing capacity than virgin soil alone. Also, it should be noted that walls made from mixes of tire shreds and sand had less horizontal displacement than a wall made with virgin soil. From this point, it is received that adding the tire shreds to the wall backfill causes better performance of the wall both in the field of bearing capacity and horizontal displacement of the wall compared to the virgin soil without tire shreds. 6. Regarding the results of the experiments, it is suggested that instead of traditional rubber disposal methods such as incineration, accumulation, and unprincipled burial which have many risks and environmental pollution, tires be turned into tire shreds and used as fillers in earthen projects such as retaining walls and road embankments. Declarations Founding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Conflicted of interest Not applicable Competing Interests The authors have no relevant financial or non-financial interests to disclose. Code availability Not applicable Available dataand materials The obtained data from experiments are in the result and discussion section, if you need the details of laboratory results, we can send an excel file References ASTM, D.-. (2008). Standard practice for use of scrap tires in civil engineering applications. 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Journal of Geotechnical and Geoenvironmental Engineering, 145(11), 06019012. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 09 Aug, 2023 Read the published version in Arabian Journal for Science and Engineering → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1925499","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":126413509,"identity":"6cb8bfd2-9fc2-4883-892f-3e9f9dbcbb78","order_by":0,"name":"Michael Kazemzadeh","email":"","orcid":"","institution":"Islamic Azad University, Tehran","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Michael","middleName":"","lastName":"Kazemzadeh","suffix":""},{"id":126413510,"identity":"a3809cd2-5051-4408-9f0e-b8107524acb3","order_by":1,"name":"Matin Jalali Moghadam","email":"","orcid":"","institution":"Islamic Azad University, Tehran","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Matin","middleName":"Jalali","lastName":"Moghadam","suffix":""},{"id":126413511,"identity":"54823534-1fbb-467b-8d22-e05a43bb5066","order_by":2,"name":"Amirali Zad","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzElEQVRIiWNgGAWjYLACngoJEMXGgCAJajkD0sJMihbeNgaEFoKAv4H94Ye38yzkDY6fP/aAocaOgU/6AH4tEgcYkiXnbpMw3HAmmd2A4VgyAxtfAgFrDjAckObdJsG44QYzmwQD2wEGNh4COuQPMDb/5p0jYQ/R8o8ILQYHmNmkeRskEsFaGNuI0GJ4mI3Ncs4xieSZZ5LNDRL7knkIapE73v74xpuaOtu+4wefPfjwzU5OvoeAFgZmZE4CMFoJaRgFo2AUjIJRQAQAAN6jNmFfbhtlAAAAAElFTkSuQmCC","orcid":"","institution":"Islamic Azad University, Tehran","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Amirali","middleName":"","lastName":"Zad","suffix":""}],"badges":[],"createdAt":"2022-08-03 11:44:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1925499/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1925499/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s13369-023-08184-y","type":"published","date":"2023-08-10T01:08:46+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":24930148,"identity":"85d95d23-8fd3-4b57-8e6d-ce423a25663a","added_by":"auto","created_at":"2022-08-08 16:04:13","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":188991,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic and real view of retaining wall modeling in laboratory\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig01.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/68b98f5befc845b3310f9be2.png"},{"id":24929827,"identity":"08070138-3c17-42da-be39-e58d01a881ea","added_by":"auto","created_at":"2022-08-08 15:59:13","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":7169,"visible":true,"origin":"","legend":"\u003cp\u003eReinforcement configurations\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig02.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/946a4862e1a9c89a95ed814b.png"},{"id":24930151,"identity":"d8d840fe-241e-46a1-a87f-bb8cfd06ac46","added_by":"auto","created_at":"2022-08-08 16:04:13","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":135736,"visible":true,"origin":"","legend":"\u003cp\u003eAnchor plates\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig03.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/5aa95f3d895f7cf009e2ec63.png"},{"id":24931075,"identity":"570e3fec-9578-404a-8834-ac1d9a4a2789","added_by":"auto","created_at":"2022-08-08 16:14:14","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":61148,"visible":true,"origin":"","legend":"\u003cp\u003ePlate anchors used for modeling\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig04.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/07083a8c64a5fc7b941018fd.png"},{"id":24931550,"identity":"0a85354e-178a-47c4-936e-a5529478fb68","added_by":"auto","created_at":"2022-08-08 16:19:14","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":615833,"visible":true,"origin":"","legend":"\u003cp\u003ePhotos of tire shreds in experimental tests\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig05.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/1267f35f6500b89b444c387f.png"},{"id":24929838,"identity":"cfd7ea63-b374-4770-88d1-31beb8727a15","added_by":"auto","created_at":"2022-08-08 15:59:14","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":450621,"visible":true,"origin":"","legend":"\u003cp\u003eA view of the test chamber and used components in the experimental study\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig06.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/f959c5b039d2fac82a9efd79.png"},{"id":24929836,"identity":"b28d4f58-ea8d-4bb6-a48f-0f13437175fa","added_by":"auto","created_at":"2022-08-08 15:59:14","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":134935,"visible":true,"origin":"","legend":"\u003cp\u003eDiagrams of loading heel settlement versus the bearing capacity based on width and aspect ratio of tire shred\u003c/p\u003e","description":"","filename":"Fig07.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/35a0c9dbaf1ad8a971508d0d.png"},{"id":24930576,"identity":"016113f2-13b5-489e-b577-1c3599c2cbb4","added_by":"auto","created_at":"2022-08-08 16:09:13","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":130348,"visible":true,"origin":"","legend":"\u003cp\u003eDiagrams of loading heel settlement versus the horizontal wall displacement based on width and aspect ratio of tire shreds\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig08.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/208318ea4b87c5b744f90fea.png"},{"id":24930154,"identity":"87734d68-6ca1-491c-b46a-f0470bce397d","added_by":"auto","created_at":"2022-08-08 16:04:14","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":732344,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of PIV for embankments with tire shreds with dimensions of 1 cm\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig09.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/4b862bf74e5e342d5a431896.png"},{"id":24929840,"identity":"353b48bf-6443-4c1d-8a40-ef418826abd2","added_by":"auto","created_at":"2022-08-08 15:59:14","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":826665,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of PIV for embankments with tire shreds with a width of 2 cm\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig10.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/b2eefed14a8cfce3d55015ac.png"},{"id":24930574,"identity":"73b6ca1a-31f5-4f7e-81bd-cb484563d040","added_by":"auto","created_at":"2022-08-08 16:09:13","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":101113,"visible":true,"origin":"","legend":"\u003cp\u003eAnalysis of PIV for embankments without tire shreds (virgin soil)\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig11.png","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/a6fa517bb5170ba0c631ae1a.png"},{"id":53765406,"identity":"129a15e5-69f3-41be-a50c-d3b1856d0448","added_by":"auto","created_at":"2024-03-30 01:08:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3923429,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1925499/v1/666a00b8-6aea-437f-9e46-8fa1d1201e58.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Influence Of Tire-Shreds' Aspect Ratio On Performance Of Mechanically Stabilized Retaining Walls","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eCurrently, the volume of scrap tires increases dramatically with raising the number of vehicles. As a result, large warehouses are needed to store these tires. Regarding the lack of space required to store these tires and the danger involved in storing tires (e.g., fire and growth of vermin and insects), reuse and recycling of these tires have been considered a potential solution. Tire shreds are a group of shredded recycled tires with different shapes and sizes, usually varying between 50 and 300 mm according to ASTM (\u003cspan class=\"CitationRef\"\u003e2008\u003c/span\u003e). Tire shreds used in the construction of embankments have the maximum aspect dimensions of 150 to 300 mm. These shreds have several applications, such as filling materials for embankments or retaining walls backfill. Among the essential properties of these materials are their low weight and low cost. Hataf and Rahimi (\u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e) tested the bearing capacity of sand reinforced with tire shreds with a width of 2 and 3 cm, aspect ratios of 2, 3, 4, and 5, and the shreds to sand ratios of 10, 20, 30, 40, and 50 vol.%. The authors concluded that the addition of tire shreds to the sand increases the bearing capacity ratio (BCR) from 1.17 to 3.9, depending on the content of the tire shreds and the aspect ratio. The maximum BCR is obtained in 40 vol.% and 3 \u0026times; 12 cm dimensions. Also, the results showed that the BCR is incremented by increasing the tire shreds content. However, an optimal value is observed for the tire shreds content; exceeding the tire shreds increases leads to a reduction in BCR. Attom (\u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e) combined three different sand models with tire shreds that passed through sieve number #4 at 10, 20, 30, and 40 wt.% and performed the direct shear test on the samples to obtain the shear strength parameters of sand-containing mixes. Based on the results of Attom\u0026apos;s study, with increasing the percentage of tire shreds, both the internal friction angle and the shear strength of sand increased. Meanwhile, an increment in the initial dry unit weight (\u0026gamma;\u003csub\u003edry\u003c/sub\u003e) of the sand and tire shreds mixture increased the shear strength. Warith and Rao (\u003cspan class=\"CitationRef\"\u003e2006\u003c/span\u003e) performed a series of one-dimensional compression tests on four tire shreds samples and compared the results with previous studies\u0026apos; stress/strain curves. The results suggested that despite experiencing large axial strains, the average permeability of the tire shreds sample consistently remained two to three orders of magnitude higher than the design performance criterion of 0.01 cm/s for landfill drainage layers. Balunaini and Prezzi (\u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e) performed pullout experiments to investigate the interaction between ribbed-metal-strip reinforcement in mechanically stabilized earth walls with tire shreds. The studied soil was Ottawa sand, the size of the tire shreds was 9.5 mm, 50 to 100 mm, and 100 to 200 mm, and the weight percentage was 0, 12, 25, and 100 wt.%. Finally, the results indicated that the pullout capacity of ribbed metal strips embedded in tire shred\u0026ndash;sand mixtures is much higher than that of ribbed metal strips embedded in samples prepared with only tire shreds. Also, the effect of tire shreds size on the pullout capacity of metal strips for mixtures prepared with low or high tire shreds content (12 or 100 wt.%) was negligible. Tafreshi and Norouzi (\u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e) combined 10 mm wide tire shreds with an aspect ratio of 3 to 5 with sand and performed bearing capacity tests on a mixture in the laboratory. According to the results, rubber reinforcement efficiency was enhanced by adding rubber content, the thickness of the rubber-reinforced soil layer, and the soil cap thickness up to the optimum values of these parameters. Mohan et al. (\u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e) conducted a series of pullout tests on ladder-type metal reinforcements in mechanically stabilized earth (MSE) walls reinforced with mixtures of Ottawa sand with 50\u0026ndash;100 mm size tire shreds at different mixing ratios (0, 20, 25, and 35 wt.% of tire shreds). They concluded that the ladder-type metal reinforcement provides higher pullout resistance in tire shred-sand mixtures than in sand alone. Also, they reported that the pullout resistance increased with increasing tire shreds content up to 35% (by weight of tire shreds). Ghazavi et al. (\u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e) performed a study on the sand-tire shreds mixture to obtain the optimal volume of tire shreds in the mixture with sand. In this study, the size of the tire shreds was 0.2, 0.3, and 0.4 times footing width. They concluded that 10\u0026ndash;15 vol.% is the optimum percentage of tire shreds by volume in the granular trench. They also showed that the footing bearing capacity improves by increasing the size of the tire shreds and increasing the thickness of the tire shred-mixed zone in the granular trench. Madhusudhan et al. (\u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e) combined 2mm rubber tire shreds with sand with 0, 10, 30, 50, and 100 wt. % of rubber tire shreds and performed permeability, compression, and uniform direct shear tests on them. According to their results, the permeability of mixtures decreases with increasing the percentage of tire shreds. Bahadori and Farzalizadeh (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e) combined tire powder and tire shreds with dimensions of 1\u0026times;3 cm and 5, 10, 20, and 30 wt.% of 161 Firuzkuh sand and then conducted a series of 1 g shaking table model tests. The results indicated that tire powders and tire shreds decline pore-water pressure due to liquefaction. Also, the maximum shear modulus of reinforced soil incremented with increasing tire powder content in the mixture. Shariatmadari et al. (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e) investigated the effect of using tire shreds on stone columns. For this purpose, and to investigate the effects of the tire shreds, they performed a series of large-scale direct shear, large-scale oedometer, and constant head permeability tests. The tire shreds used in these tests consisted of 3 different sizes and an aspect ratio of 2. The large-scale direct shear box and oedometer tests demonstrated a 30% increase in the loading capacity of stone columns for 20% of tire content. However, the loading capacity of the stone column declined for tire mixing ratios greater than 20%. Madhusudhan et al. (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e) performed dynamic simple shear tests on a mixture of sand and tire shreds with dimensions of 2 mm and 10, 30, and 50 wt.% and compared the test results with those of cyclic triaxial tests. They concluded that the cyclic triaxial tests overestimated the shear moduli, but the damping ratios were comparable to those obtained from dynamic simple shear testing. Xiao et al. (\u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e) performed thermal conductivity tests on a mixture of sand and tire shreds with dimensions from 0.25 to 4 mm and volume percentages of 0, 10, 20, 30, and 40. They concluded that using tire shreds with a larger relative size ratio yields higher thermal conductivity. Also, in this study, the maximum variation in the thermal conductivity percentage difference with the relative size ratio reached about 20% at a volumetric mixing ratio of 40%. Madhusudhan et al. (\u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e) performed a series of conventional triaxial shear tests, direct shear tests, and dynamic triaxial tests on sand-tire shreds mixture with 0, 10, 30, 50, and 100 wt.%. The maximum size of the tire shreds was 2 mm. They concluded that increasing the percentage of tire shreds reduces the internal friction angle. Also, the effect of confining stress and the shearing rate on the angle of internal friction is negligible. Khan et al. (\u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e) combined sand and tire shreds with dimensions of 50, 75, and 100 mm and 0, 20, 30, and 40 wt.%. They performed modified proctor compaction tests, large-scale direct shear tests, and pullout tests. According to their results, the internal friction angle (\u0026phi;) for sand-tire shreds mixture (30:70) with 100 mm tire shreds size was 38.5\u0026deg; and for the sand-only mixture (100:0) was 30.9\u0026deg;. This difference is because the tire shreds are randomly distributed in the shear zone and therefore have a higher slip resistance. Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e provides a summary of past research on recycled tires.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eA set of tests performed on recycled tires and their results\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAuthor (s)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eType of recycled tire\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTest\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAspect ratio/Dimension\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eReported findings\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEdin\u0026ccedil;liler and Ayhan (\u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Crumb \u0026amp; Tire Buffings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStandard direct shear test \u0026amp; large-scale direct shear tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire crumb with a size of 1 to 3 mm,\u003c/p\u003e\n \u003cp\u003eTire Buffings with a size between sieves#4(4.75mm) and #10 (2mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThree factors significantly affecting the shear strength values were normal stress, aspect ratio, and tire waste content. Also, increasing the aspect ratio of the fibers increases the shear strength of the mixture.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEdin\u0026ccedil;liler et al. (\u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire crumb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLarge-scale direct shear tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 to 3 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSand-tire mixtures have higher shear strength than the sand alone. The shear strength parameters depend on the processing conditions of used tires. Three factors significantly affect the mechanical properties: normal stress, processing techniques, and the used tire content.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAyothiraman and Soumya (\u003cspan class=\"CitationRef\"\u003e2011\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Chips\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTriaxial tests (UU \u0026amp; CD)-Load-displacement response\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMixtures of 60%T\u0026thinsp;+\u0026thinsp;40%S and 40%T\u0026thinsp;+\u0026thinsp;60S have the load-carrying capacity of a stone column with only stone aggregates (100S). This result demonstrates that waste tire chips can be used to partially replace stone aggregates up to about 60% in stone columns.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEdincliler et al. (\u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Crumb \u0026amp; Tire Buffings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTriaxial tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire crumbs with an aspect ratio of 1 to 1.5. Tire buffings with an aspect ratio of 3.5 to 4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe NN-based constitutive model is observed to be very close to actual experimental results. The proposed NN models are also expressed as simple mathematical functions for practical use.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEdincliler et al. (\u003cspan class=\"CitationRef\"\u003e2013\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Crumb \u0026amp; Tire Buffings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCyclic triaxial tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire buffings with an aspect ratio of 1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe greater the proportion of waste tire crumbs or tire buffings on the sand, the greater is the damping ratio, the less is the shear modulus, regardless of confining pressure.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLi et al. (\u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire crumb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResonant column tests and cyclic triaxial tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.18 to 0.25 mm and 0.6 to 0.85 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe mix ratio affects the dynamic shear modulus significantly and the liquefaction susceptibility.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBrara et al. (\u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Rubber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eModified triaxial cell test with bender elements\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.06 to 0.60 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe shear modulus decreases with increasing rubber volume fractions for all confining pressures, while the damping ratio increases linearly.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eWang et al. (\u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Shred\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eResonant column tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e50\u003c/sub\u003e: 1.52 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe increase in shear strain reduces the maximum dynamic shear modulus but raises the damping ratio of the sand-rubber mixtures. As the dynamic shear modulus of the mixtures increments, the damping ratio declines with an increase in confining pressure.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMazumder et al. (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Chips\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLarge-scale direct shear tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10 mm \u0026times; 10 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe ordinary stone columns made of stone aggregates can be replaced by encased stone columns made of 100% tire chips.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eKaushik et al. (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Chips\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHydraulic conductivity tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAspect ratio: 1 to 4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe combination of the TS1 size tire chips with gravel in the mixing ratio of 1:3 outperformed the other mixes. The hydraulic conductivity reduction was comparatively lower even on higher stress levels.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMoghadam et al. (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire crumb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReduced scale model tests to investigate\u003c/p\u003e\n \u003cp\u003ethe behavior of MSE walls subjected to static loading\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePassing through sieve #4 (4.75 mm) and remaining on sieve #6 (3.35 mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe circular anchor plates almost continually provided a higher bearing capacity and wall stability than the square plates. Moreover, the backfill with 15 wt.% RCR provided the maximum bearing capacity of the wall.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBoominathan and Banerjee (\u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire Shred\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMonotonic direct shear tests, one-dimensional\u003c/p\u003e\n \u003cp\u003ecompression, permeability tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIntriguingly, the permeability of the mixtures reduces with an increase in rubber content. The contact angles of sand-water and the rubber-water interfaces determined using a Goniometer explain this behavior.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBahadori and Khalili (\u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire powders\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1-g shaking table tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e30\u003c/sub\u003e of Tire Powders: 0.41 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIn all cases, the increase in frequency in the same cycles built up the shear modulus and the damping ratio. Also, with increasing shear strain, the shear modulus of the mixture decreased, but the damping ratio incremented.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSarajpoor et al. (\u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTire crumb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHollow cylinder test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e50\u003c/sub\u003e: 0.83, 2.33, 6 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDynamic properties of sand-crumb rubber mixtures were mainly influenced by rubber content and confining stress values. In this process, relative density and rubber particle size were less effective in this regard.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMoussa and El Naggar (\u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTDA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCyclic triaxial test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.53 to38.1 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe shear modulus decreases with increasing shear strain amplitudes. Also, it has a similar trend to natural granular soils.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEl Naggar and Iranikhah (\u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTDA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLarge-scale direct shear\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30\u0026ndash;40 mm, 40\u0026ndash;50 mm,50\u0026ndash;60 mm, 60\u0026ndash;70 mm, and 70\u0026ndash;75 mm.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe addition of TDA to the considered soils significantly reduces the dry unit weight, making the mixtures attractive for applications requiring lightweight fill materials.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEl Naggar and Zahran (\u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTDA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLarge-scale triaxial tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003emax\u003c/sub\u003e of 19.05,\u003c/p\u003e\n \u003cp\u003e25.4, 38.1, 50.8, and 76.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe shear strength of TDA builds up by incrementing the maximum particle size, while the cohesion did not have a specific trend. Moreover, the samples exhibited a rise in the secant elastic modulus by increasing the particle size\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEl Naggar et al. (\u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTDA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLarge-scale direct shear tests\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.5\u0026ndash;101.6 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eThe angle of internal friction (\u0026phi;) rose with increasing the maximum particle size. Moreover, the secant shear modulus also exhibited an increase by increasing the maximum particle size.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eFor the first time, Moghadam et al. (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e) used plate anchors vertically in the retaining walls. In this research, the effect of adding recycled crumb rubber in the backfill of the mechanically stabilized earth wall with plate anchors with different characteristics was investigated. The results of this study showed that larger plate anchors had more bearing capacity and with increasing the amount of recycled crumb rubber, the horizontal displacement of the wall decreases. Moghadam et al. (\u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e) conducted experimental modeling to study the effect of using vertical plate anchors with different shapes \u0026amp; configurations in mechanical stabilized earth walls. Results of this research indicated that circular plate anchors had the most bearing capacity and using a diamond reinforcement configuration provides more bearing capacity than a square reinforcement configuration.\u003c/p\u003e\n\u003cp\u003eThe present paper considers the experimental tests on the bearing capacity of mechanically stabilized walls reinforced by plate anchors, where the backfill material is a mixture of soil and tire shreds which was not subject to study till now. The factors evaluated for this purpose include changes in weight percentage and aspect ratio of tire shreds on the bearing capacity of the wall, deformations and horizontal displacements of the wall, and the formation of critical slip surfaces or wedge rupture. Also, the particle image velocimetry (PIV) technique was employed to observe the slip surfaces formed in the retaining wall backfill.\u003c/p\u003e"},{"header":"2. Experimental Tests","content":"\u003cp\u003eExperiments were performed on a laboratory scale using a 1: 10 scale. Based on this scale, the length, width, and height of the retaining wall were scaled from 7 \u0026times; 5 \u0026times; 5 m to 70 \u0026times; 50 \u0026times; 50 cm. The face of permanent retaining walls was built using prefabricated or integrated concreted concrete panels. Like the study of Moghadam et al., (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e), the face of the retaining wall was manufactured using an aluminum sheet with a thickness of 0.9 mm (equivalent to a 30-cm concrete face) based on the recommendation by Wood (\u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e). A chamber with a length of 124 cm, a width of 53 cm, and a depth of 82 cm was manufactured to build the retaining walls. The purpose of increasing the length and depth of the chamber is to prevent boundary effects. To observe the soil\u0026apos;s failure wedge, tempered glass with a thickness of 30 mm was used on one side of the chamber. This thickness of tempered glass was chosen to ensure that it did not deform and bulge during loading. Also, 20 cm of soil was placed under the wall as an earthen bed. Figure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e illustrates a schematic of the test chamber, loading system, load cell, strain gauges, and loading heel.\u003c/p\u003e\n\u003cp\u003eThe soil used in all experiments was dry sand from the Soufian region of East Azerbaijan province, which was classified as poorly graded sand (SP) according to the Unified Soil Classification System (USCS). The soil properties are displayed in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003esoil properties\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"12\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eϕ\u003c/em\u003e (\u0026deg;)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u0026Upsilon;\u003csub\u003edmin\u003c/sub\u003e (kN/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u0026Upsilon;\u003csub\u003edmax\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(kN/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eG\u003csub\u003es\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ee\u003csub\u003emin\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ee\u003csub\u003emax\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e60\u003c/sub\u003e (mm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e50\u003c/sub\u003e (mm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e30\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(mm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eD\u003csub\u003e10\u003c/sub\u003e (mm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eC\u003csub\u003ec\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eC\u003csub\u003eu\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.87\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.36\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003ePlane strain conditions were established using a loading heel with a length of 50 cm, a width of 10 cm, and a height of 3 cm (The loading heel is equivalent to the strip footing.). The friction between the lower part of the loading heel and the soil was reduced by thoroughly polishing all parts of the loading heel. The length of the anchor rod used in this research is 50 cm, which is equivalent to a 5-m anchor rod by applying a scale factor of 1:10. The diameter of the anchor rod is 4 mm, which was equivalent to 4 cm in diameter rebar. Using the results of Moghadam et al., (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e), the arrangement of anchors was selected as a diamond (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). The reason for choosing this configuration is that they showed the superiority of the diamond arrangement to other ones (square and even 5-anchor) in terms of higher bearing capacity and lower horizontal displacement. The center-to-center distance of the anchors in the horizontal and vertical directions was considered 30 cm.\u003c/p\u003e\n\u003cp\u003eFurthermore, using the results of Moghadam et al., (\u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e), the shape of the anchor plates was chosen as a square. The square plates had dimensions of 2.6 cm and a thickness of 3 mm (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). Three-plate square reinforcements with a 12- cm center-to-center distance were considered in This configuration (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eThe tire shreds used were all free of yarn and metal. In all tests, the tires\u0026rsquo; thickness was 2 mm, widths of 2 and 1 cm, and aspect ratios of 1, 2, 3, 4, and 5 (Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e). These tire shreds were mixed with Soufian sand soil at 5, 10, 15, and 20 wt.% and used as backfill material for the retaining wall. Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e presents the specifications of the tire shreds, including their aspect ratio. Figure\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e shows the photos of tire shreds for experimental tests.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab3\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eDimensions of the tire shreds in the Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRow\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eID in Fig. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eDimensions (cm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eWeight percentages (%)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ea\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1*1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eb\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1*2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ec\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1*3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ed\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1*4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ee\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1*5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ef\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2*2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2*4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2*6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ei\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2*8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ej\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2*10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5, 10, 15, 20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"3. Method Of Experiments","content":"\u003cp\u003eFirstly, for determining the strength parameters of sand-tire shred mixtures, standard direct shear tests were conducted based on ASTM (\u003cspan class=\"CitationRef\"\u003e2011\u003c/span\u003e) on sand-tire shred mixtures. For this purpose, the authors used a large-scale direct shear apparatus with a dimension of 30 * 30cm.\u003c/p\u003e\n\u003cp\u003eSecond, The effects of tire shreds\u0026rsquo; weight percentage and aspect ratio were investigated by performing 41 tests. In all tests, the unit weight of sand was 15.36 kN/m3, i.e., a relative density of 50%. At first, the Sufian sand soil and tire shreds were mixed. Then, the sand precipitation method was performed to reach the desired relative density.\u003c/p\u003e\n\u003cp\u003eThe applied load was measured by a 2-ton load cell and captured via a data logger connected to the laptop. All tests were performed under constant strain conditions with six steps of 5 mm to achieve the highest possible loading rate accuracy. All experiments were performed in 7 stages, the first stage was load-free, and only the first photo of the wall surface was taken. The settlement related to the applied load was controlled using a strain gauge. Also, the horizontal wall displacement was measured using three strain gauges installed on the wall face. The first strain gauge was installed at a distance of 3 cm from the edge of the face, the second strain gauge at a distance of 15 cm from the first one, and the third strain gauge at a distance of 15 cm from the second one. A view of the test chamber and its components are shown in Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e"},{"header":"4. Experimental Test Results","content":"\u003cdiv class=\"Section2\" id=\"Sec5\"\u003e\n \u003ch2\u003e4.1. Direct shear tests results\u003c/h2\u003e\n \u003cp\u003eThe results of the direct shear tests are presented in Table. 4. Based on obtained results, it was revealed that for all tire shreds with a width of 1 and 2cm in a constant weight percentage in tire shred-sand mixtures, both the internal friction angle and cohesion of the mixture will be incremented. It means that the maximum internal friction angle and cohesion of mixtures were belongs to mixtures consisting of tire shreds with an aspect ratio of 5 (1*5 and 2*10). Also, the results show that in a constant aspect ratio of tire shreds, increasing tire shreds weight percentage in mixtures will increase the internal friction angle and cohesion of the mixtures. The maximum internal friction angle and cohesion of the sand-tire shred mixtures belong to mixtures with 20% content of tire shreds.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab4\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eresults of direct shear tests\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"10\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRow\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTire shred\u0026apos;s dimension\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTire shred\u0026apos;s content\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ec(kPa)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u0026Phi;\u003c/p\u003e\n \u003cp\u003e(degree)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRow\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTire shred\u0026apos;s dimension\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTire shred\u0026apos;s content\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ec(kPa)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u0026Phi;\u003c/p\u003e\n \u003cp\u003e(degree)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e2.2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e28.2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e21\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e12.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e35.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e4.8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e29.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e22\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n 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\u003cp\u003e\u003cstrong\u003e28.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e40.9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e11\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e23.6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e33.7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e31\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e30.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e41.2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e12\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e25.6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e37.9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e32\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e32.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e42.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e13\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e14.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e31.6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e33\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e24.7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e38.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e14\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e18.7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e32.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e34\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e29.6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e41\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e25.8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e34.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e35\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e32.6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e42.4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e16\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e32.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e38.3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e36\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e34.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e42.9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e17\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e23.6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e34.9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e37\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e25.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e39.8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e18\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e24.5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e35.7\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e38\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e30.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e41.6\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e19\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e28.2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e36.8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e39\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e15\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e34.2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e42.2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1*5\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e33.1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e38.8\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e40\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2*10\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e20\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cstrong\u003e35.4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e43.9\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec6\"\u003e\n \u003ch2\u003e4.2. Bearing capacity evaluation\u003c/h2\u003e\n \u003cp\u003eThe mixes containing 5% of tire shreds with a width of 2 cm revealed that the highest bearing capacity (i.e., 58 kPa) was obtained from tire shreds with 2\u0026times;10 cm dimensions (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003ea). The wall, backfilled with mixes of tire shreds and sands with dimensions of 2\u0026times;8, 2\u0026times;6, 2\u0026times;4, and 2\u0026times;2 cm was, reached the bearing capacity of 53.5, 51.3, 32.1, and 30.6 kPa, respectively. Analyzing the load-bearing capacity of the mixes containing 5% tire shreds with 1 cm width demonstrated that tire shreds with dimensions of 1\u0026times;5 were shown the maximum load-bearing capacity (44 kPa) of the wall, among others. The mixes containing tire shreds with dimensions of 1\u0026times;4, 1\u0026times;3, 1\u0026times;2, and 1\u0026times;1 cm were in the next rank in terms of the bearing capacity (i.e., 30.5, 24.5, 19.6, and 16.6 kPa, accordingly). Comparing the results of bearing capacity obtained from the mixes containing 5% of tire shreds indicates that the tire shreds with dimensions of 1\u0026times;5 cm had a higher bearing capacity compared to tire shreds with dimensions of 2\u0026times;4 \u0026amp; 2\u0026times;2 In addition, the optimum dimensions in terms of the amount of loading in the constant settlement applied in the experimental tests in 5% of tire shreds were 2\u0026times;10 and 2\u0026times;8 cm, respectively.\u003c/p\u003e\n \u003cp\u003eAccording to Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(a) (mixed with 5% of tire shreds with a width of 1 cm), raising the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5 will lead to an increase in bearing capacity by 18%, 25%, 24.4%, and 44.2%, respectively.\u003c/p\u003e\n \u003cp\u003eBased on Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(b), for mixed with 5% of tire shreds with a width of 2 cm, as the aspect ratio increases from 1 to 2, 2 to 3, 3 to 4 m, and 4 to 5, the bearing capacity of the wall will increase by 1.3%, 59.8%, 4.3%, and 8.4% respectively.\u003c/p\u003e\n \u003cp\u003eThe results of tests performed with 10 wt.% of tire shreds with a width of 1 cm are presented in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(c). As can be seen, the most considerable bearing is related to the test performed with 1\u0026times;5- cm tire shreds. In this test, the load recorded on the wall backfill was 46.2 kPa. Finally, the mixes containing tire shreds with dimensions of 1\u0026times;4, 1\u0026times;3, 1\u0026times;2, and 1\u0026times;1 had bearing capacities of 35.3, 34.3, 25.4, and 24.7 kPa, respectively. Also, according to results presented in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(d), the mixes containing 10 wt.% of tire shreds with a width of 1 cm showed that mixes with 2\u0026times;10 cm tires had the highest bearing capacity (i.e., 84.1 kPa) among the tire shreds with a width of 2 cm and 10 wt.%. In the next rank, the mixes containing tire shreds with dimensions of 2\u0026times;8, 2\u0026times;6, 2\u0026times;4, and 2\u0026times;2 cm had a bearing capacity of 80.2, 75.7, 38.1, and 32.3 kPa, accordingly.\u003c/p\u003e\n \u003cp\u003eComparing the results obtained from the tests performed on a mix with a 10 wt.% of tire shreds and a width of 1 and 2 cm showed that the tire shreds with dimensions of 1\u0026times;5 cm compared to the tire shreds with dimensions of 2\u0026times;4 and 2\u0026times;2 cm had higher bearing capacities. In addition, tire shreds with dimensions of 1\u0026times;4 and 1\u0026times;3 had better bearing capacity at 10 wt.% than tire shreds with dimensions of 2\u0026times;2 cm. In the tests performed at 10 wt.%, the best and highest bearing capacities were related to tire shreds with dimensions of 2\u0026times;10 and 2\u0026times;8 with bearing capacities of 84.1 and 80.2 kPa, respectively.\u003c/p\u003e\n \u003cp\u003eAnalysis of the results obtained from tests performed with 1-cm width tire shreds reveals that at 10 wt.%, with raising the aspect ratio raises from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, wall bearing capacity elevated by 2.8%, 35%, 2.9%, and 30.9%, accordingly.\u003c/p\u003e\n \u003cp\u003eIn mixes containing 10 wt.% of tire shreds and a width of 2 cm, with increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and from 4 to 5, wall bearing capacity incremented by 18%, 98.7%, 5.9%, and 4.8% respectively.\u003c/p\u003e\n \u003cp\u003eThe results of tests performed with 15 wt. % of the tire shreds (Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(e) show that in the tests with 1-cm width of tire shred, the highest bearing capacity was related to the tire shreds with dimensions of 1\u0026times;5 cm and bearing capacity of 71.5 kPa. In the next rank, the mixes containing tire shreds with dimensions of 1\u0026times;4, 1\u0026times;3, 1\u0026times;2, and 1\u0026times;1 recorded 49.4, 43.5, 35.5, and 25.3 kPa bearing capacities, respectively. The test performed with 15 wt.% of tire shreds with 2\u0026times;10 cm dimensions indicated that tire shreds with 15 wt.% and 2\u0026times;10 cm dimensions had a higher bearing capacity than the other tire shreds with a width of 2 cm. The results revealed that the mixture of sand and 2\u0026times;10 cm tire shreds was loaded by 120.2 kPa at 15 wt.%. According to results shown in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(f), mixtures containing tire shreds with dimensions of 2\u0026times;8, 2\u0026times;6, 2\u0026times;4, and 2\u0026times;2 had bearing capacities of 88.9, 83.4, 64.7, and 49.2 kPa, respectively. Comparing the results obtained for tire shreds with a width of 1 and 2 cm at a weight of 15% exhibited that the soil reinforced with 1\u0026times;5 cm tire shreds had a higher bearing capacity than the soil reinforced with 2\u0026times;4 and 2\u0026times;2 cm tire shreds. Also, sand soil reinforced with 1\u0026times;4 cm tire shreds had a slight bearing capacity difference with sandy soil reinforced with 2\u0026times;2 cm tire shreds.\u003c/p\u003e\n \u003cp\u003eThe highest bearing capacity in the mentioned tests for the weight percentage of 15% of tire shreds was related to the soil reinforced with 2\u0026times;10 cm tire shreds with a bearing capacity of 120.2 kPa. On the other hand, the lowest bearing capacity was related to the soil reinforced with 1\u0026times;1 cm tire shreds with a bearing capacity of 25.3 kPa.\u003c/p\u003e\n \u003cp\u003eIn mixes containing 15 wt.% of tire shreds and a width of 1 cm, with increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, wall bearing capacity increased by 40.3%, 22.5%, 13.6%, and 44.7%, respectively.\u003c/p\u003e\n \u003cp\u003eAlso, in mixes containing 15 wt.% of tire shreds and a width of 2 cm, with increasing the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the bearing capacity of the wall incremented by 31.5%, 28.9%, 1.8%, and 41.6%, accordingly.\u003c/p\u003e\n \u003cp\u003eThe results obtained from tests performed with tire shreds with a width of 1 cm at 20 wt.% are shown in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(g). Among the tire shreds with a width of 1 cm at 20 wt.%, those with dimensions of 1\u0026times;5 cm had a better bearing capacity (i.e., 83.3 kPa) than the tire shreds with a width of 1 cm. In the next rank, the tire shreds with dimensions of 1\u0026times;4, 1\u0026times;3, 1 \u0026times;2, and 1\u0026times;1 cm had bearing capacities of 76.5, 56.8, 38.2, and 33.3 kPa, respectively. Also, according to Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(h) results, mixes containing 20 wt.% of tire shreds with a width of 2 cm show that tire shreds with dimensions of 2\u0026times;10 cm and a bearing capacity of 156.5 kPa had the highest bearing capacity among tire shreds with a width of 2 cm. Next, tire shreds with dimensions of 2\u0026times;8, 2\u0026times;6, 2\u0026times;4, and 2\u0026times;2 cm and bearing capacity of 151.1, 111.4, 87.4, and 52.5 kPa, respectively, were placed in the following ranks compared to tire shreds with dimensions of 2\u0026times;10 cm.\u003c/p\u003e\n \u003cp\u003eIn the mixes containing soil and 20 wt.% of the tire shreds, the mixes containing tire shreds with dimensions of 1\u0026times;5, 1\u0026times;4, and 1\u0026times;3 cm had higher bearing capacity than the tire shreds with dimensions of 2\u0026times;2 cm. The highest bearing capacity in the mixtures of soil and 20 wt.% of tire shreds was related to the mixture of soil and tire shreds with dimensions of 2\u0026times;10 cm and a bearing capacity of 156.5 kPa. Also, as in the previous results, the lowest bearing capacity was related to the mixture of soil and 1\u0026times;1 cm tire shred.\u003c/p\u003e\n \u003cp\u003eSoil mixes containing 20 wt.% of tire shreds and a width of 1 cm indicate that by raising the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the bearing capacity of the wall incremented by 14.7%, 48.7%, 34.7%, and 8.9%, respectively.\u003c/p\u003e\n \u003cp\u003eIn mixes containing 20 wt.% of tire shreds with a width of 2 cm, with increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the wall bearing capacity increased by 66.5%, 27.5%, 35.6%, and 3.3% accordingly.\u003c/p\u003e\n \u003cp\u003eThe study of the obtained bearing capacity shows that by increasing the aspect ratio of the tire shreds at a constant weight percentage (increasing the dimensions), the bearing capacity of the mixture increased. Also, with the constant dimensions and aspect ratio of tire shreds, increasing the weight percentage of tire shreds from 5 to 20 leads to a high bearing capacity of mixtures.\u003c/p\u003e\n \u003cp\u003eThe performed test on the retaining wall with virgin soil that has no content of tire shreds showed that the wall had a bearing capacity of 14.8 kPa. Comparing this to the results obtained from tests performed by mixtures of sand-tire shred reveal that adding tire shreds in the backfill of a retaining wall had a positive effect on the bearing capacity of the wall. Also, it was concluded that for tire shred with a width of 2cm increasing tire shred\u0026rsquo;s weight percentage from 0 to 5 in mixtures with sand, the increment in bearing capacity was more significant than for tire shred with a width of 1cm in same weight percentage. The increase in bearing capacity of the mixtures of sand-tire shreds can be related to the interlocking between sand particles and tire shreds. Increasing tire shreds\u0026rsquo; aspect ratio or weight percentage in mixes will help to strengthen the interlocking between sand particles and tire shreds and that results in an increment in the bearing capacity of walls.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec7\"\u003e\n \u003ch2\u003e4.3. Retaining wall`s stabilization\u003c/h2\u003e\n \u003cp\u003eThe results of laboratory tests regarding the horizontal wall displacement are presented in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e. As shown in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(a), the minimum wall horizontal displacement (i.e., 10.7 mm) against the applied settlement occurred in a mix containing 5 wt.% of tire shreds with a width of 1 cm and shreds dimensions of 1\u0026times;1 cm. In the next rank, mixes containing 5% tire shreds with dimensions of 1\u0026times;2, 1\u0026times;4, 1\u0026times;3, and 1\u0026times;5 cm had horizontal displacements of 10.8, 10.9, 11.2, and 11.8 mm, respectively.\u003c/p\u003e\n \u003cp\u003eBased on the results presented in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(b) for the mixes containing 5 wt.% of tire shreds with a width of 2 cm, the lowest horizontal wall displacement (i.e., 10.8 mm) was obtained for a mixture of sand and tire shreds with dimensions of 2\u0026times;2 cm. In the next rank, the mixes containing tire shreds with dimensions of 2\u0026times;4, 2\u0026times;6, 2\u0026times;8, and 2\u0026times;10 had horizontal displacements of 11.1, 11.3, 11.5, and 11.9 mm, correspondingly.\u003c/p\u003e\n \u003cp\u003eComparing the results obtained for tests performed with a mix with 5 wt.% of tire shreds and a width of 1 and 2 cm shows that the lowest horizontal wall displacement (10.7 mm) occurred in mix-tire shreds with dimensions of 1\u0026times;1 cm. Among all tests performed with a 5 wt.% mixture of tire shreds, the test performed with tire shreds with dimensions of 1\u0026times;5 and 2\u0026times;10 cm had the highest horizontal wall displacement of 11.8 and 11.9 mm, respectively.\u003c/p\u003e\n \u003cp\u003eFor mixes containing 5 wt.% of sand soil and tire shreds with a width of 1 cm, by increasing the ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, horizontal wall displacement increased by 0.9%, 0.9%, 2.7%, and 5.3% accordingly.\u003c/p\u003e\n \u003cp\u003eFor mixes with 5 wt.% of sand and tire shreds with a width of 2 cm, as the aspect ratio of tire shreds increased from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, horizontal wall displacement increased by 2.7%, 1.8%, 1.7%, and 3.4% respectively.\u003c/p\u003e\n \u003cp\u003eAs presented in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(c), the test performed with a mixture of sand and tire shreds with dimensions of 1\u0026times;1 cm and 10 wt.% had the lowest horizontal wall displacement of 10.8 mm among laboratory modeling performed with tire shreds with a width of 1 cm and 10% weight percentage. The results also revealed that by increasing the dimensions and aspect ratio of tire shreds with a width of 1 cm, the horizontal wall displacement built up by 11.4, 11.5, 12, and 12.3 mm for tests performed with tire shreds with dimensions of 1\u0026times;2, 1\u0026times;3, 1\u0026times;4, and 1\u0026times;5, correspondingly.\u003c/p\u003e\n \u003cp\u003eAmong the tests performed on mixes containing sand and tire shreds with a width of 2 cm at 10 wt.%, tire shreds with dimensions of 2\u0026times;2 cm and a horizontal wall displacement of 11 mm had the lowest horizontal displacement. In the next rank, the mixes containing tire shreds with dimensions of 2\u0026times;4, 2\u0026times;6, 2\u0026times;8, and 2\u0026times;10 cm indicated horizontal wall displacements of 11.5, 11.6, 12.1, and 12.4 mm, respectively. These results are shown in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(d).\u003c/p\u003e\n \u003cp\u003eComparing Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(c) \u0026amp; Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(d) for the mixes containing 10 wt.% of tire shreds with widths of 1 and 2 cm shows that the lowest horizontal wall displacement (10.8 m) occurred in a mix with tire shreds dimensions of 1\u0026times;1 cm. On the other hand, the highest horizontal wall displacement (12.4 mm) occurred in the mix with tire shreds with dimensions of 2\u0026times;10 cm.\u003c/p\u003e\n \u003cp\u003eAccording to horizontal displacement results of the wall versus the aspect of loading heel settlement, in a mix containing 10 wt.% of soil and tire shreds with dimensions of 1 cm, increasing the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacement increased by 5.5%, 0.9%, 4.3%, and 2.5%, correspondingly.\u003c/p\u003e\n \u003cp\u003eMixes containing 10 wt.% of sand and tire shreds with dimensions of 2 cm show that by increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacements were incremented by 4.5%, 0.9%, 4.3%, and 2.5%, respectively.\u003c/p\u003e\n \u003cp\u003eAccording to Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(e), among the mixes containing 15 wt.% of tire shreds with a width of 1 cm, the lowest horizontal wall displacement was related to the test performed with a mixture of tire shreds with dimensions of 1\u0026times;1 cm. In the above test, the horizontal wall displacement was 11.3 mm, i.e., the lowest among the mixes containing tire shreds with a width of 1 cm. After that, the mixes containing tire shreds with dimensions of 1\u0026times;2, 1\u0026times;3, 1\u0026times;4, and 1\u0026times;5 and horizontal wall displacement of 11.8, 12.1, 12.4, and 12.5 mm were placed in the following ranks.\u003c/p\u003e\n \u003cp\u003eAnalyzing the results of the mixes containing 15 wt.% of tire shreds with a width of 2 cm which was shown in Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(f) demonstrated that the lowest horizontal wall displacement (12 mm) was related to the test performed with tire shreds with dimensions of 2\u0026times;2 cm. Here, the mixtures with tire shreds with dimensions of 2\u0026times;4, 2\u0026times;6, 2\u0026times;8, and 2\u0026times;10 and horizontal wall displacement of 12.1, 12.3, 12.4, and 12.8 mm, respectively, were placed in the next ranks.\u003c/p\u003e\n \u003cp\u003eComparing the results of tire shreds with a width of 1 and 2 cm in mixtures with 15 wt.% of the tire shreds revealed that the lowest horizontal wall displacement (11.3 mm) was related to the test performed with a mixture of sand and tire shreds with dimensions of 1\u0026times;1 cm. Meanwhile, the highest horizontal wall displacement (12.8 mm) was related to the test performed with tire shreds with dimensions of 2\u0026times;10 cm.\u003c/p\u003e\n \u003cp\u003eWith increasing the aspect ratio of mixtures of 15 wt.% tire shreds with a width of 1 cm from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacement increased by 4.4%, 2.5%, 1.7%, and 1.6%, respectively.\u003c/p\u003e\n \u003cp\u003eThe test results for mixtures with 15 wt.% tire shreds with a width of 2 cm show that by increasing the aspect ratio from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacement increased by 0.9%, 1.6%, 0.8%, and 3.2%, respectively.\u003c/p\u003e\n \u003cp\u003eThe mixes containing 20 wt.% of tire shreds and a width of 1 cm (Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(g)) reveal a mixture of sandy soil and tire shreds with dimensions of 1\u0026times;1 cm and a width of 1 cm had the lowest horizontal wall displacement (12 mm). In the next rank, the mixtures with tire shreds with dimensions of 1\u0026times;2, 1\u0026times;3, 1\u0026times;4, and 1\u0026times;5 had horizontal wall displacements of 12.4, 12.5, 12.6, and 12.8 mm, respectively.\u003c/p\u003e\n \u003cp\u003eThe mixes with tire shreds with dimensions of 2\u0026times;2 cm (Fig. \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e(h) had the lowest horizontal wall displacement (12.2 mm) in the tire shreds with a width of 2 cm. In the next rank, tire shreds with dimensions of 2\u0026times;4, 2\u0026times;6, 2\u0026times;8, and 2\u0026times;10 had horizontal wall displacements of 12.6, 12.7, 13, and 14.2 mm, respectively.\u003c/p\u003e\n \u003cp\u003eComparing the results of all tests performed with mixtures of soil and 20 wt.% of tire shreds shows the lowest horizontal wall displacement (12 and 12.2 mm) occurred in the mixes with tire shreds of 1\u0026times;1 and 2\u0026times;2 cm, respectively. On the other hand, the highest horizontal wall displacement (14.2 mm) occurred in the mixes with tire shreds with dimensions of 2\u0026times;10 cm.\u003c/p\u003e\n \u003cp\u003eThe mix containing 20 wt.% of tire shreds with a width of 1 cm and sand soil indicates that by increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacements raised by 3.3%, 0.8%, and 0.8%, and 1.6%, respectively.\u003c/p\u003e\n \u003cp\u003eAlso, mixes containing 20 wt.% of tire shreds with a width of 2 cm and sand soil show that by increasing the aspect ratio of tire shreds from 1 to 2, 2 to 3, 3 to 4, and 4 to 5, the horizontal wall displacement increased by 3.3%, 0.8%, 2.4%, and 9.2%, respectively.\u003c/p\u003e\n \u003cp\u003eThe results show that the horizontal displacement of the retaining wall made from virgin soil without any tire shreds\u0026rsquo; content was 16.3 mm. Comparing this outcome to those obtained from tests conducted on sand-tire shred mixtures indicated that adding tire shreds to the backfill of the wall will result in a decrease in horizontal wall displacement. A significant decrease in the wall\u0026rsquo;s horizontal displacement was seen by increasing the tire shreds content from 0 to 5% wt in both cases in which the tire shreds dimension was 2\u0026times;2 \u0026amp; 1\u0026times;1. Also, the results show that by increasing tire shreds\u0026rsquo; content or tire shreds\u0026rsquo; aspect ratio the horizontal displacement of the retaining wall will be increased.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec8\"\u003e\n \u003ch2\u003e4.4. \u003cstrong\u003eScrap tires vs. Slip surfaces\u003c/strong\u003e\u003c/h2\u003e\n \u003cp\u003eThe slip surfaces formed in the embankment were investigated using the particle image velocimetry (PIV) technique (White et al., \u003cspan class=\"CitationRef\"\u003e2003\u003c/span\u003e). Figure \u003cspan class=\"InternalRef\"\u003e9\u003c/span\u003e shows the results of PIV analysis and processing for tests performed with tire shreds with a width of 1 cm. Also, The strain range of soil particles is shown on the right side of the figure. These results are displayed based on the weight percentage and dimensions of the tire shreds. The results of PIV analysis for tests performed with tire shreds with dimensions of 1\u0026times;1 cm at different weight percentages evidenced that by increasing the weight percentage of tire shreds with dimensions of 1\u0026times;1 cm in the mixture of sand and tire shreds the strain gradually increased. In tests performed with tire shreds with dimensions of 1\u0026times;2 and 1\u0026times;3 cm, similar to tire shreds with dimensions of 1\u0026times;1, as the weight percentage of tire shreds increases, strain built up on the slip surface will be incremented. Analysis of PIV results for tests performed with tire shreds with dimensions of 1\u0026times;4 cm indicated that in mixes containing 5 wt.% of tire shreds and having dimensions of 1\u0026times;4 cm, a wedge with a low strain rate was formed. Next, with increasing the weight percentage of the tire shred, the strain gradually increased and expanded. In mixes containing 5 wt.% of tire shreds with dimensions of 1\u0026times;5 cm, a wedge failure was formed with a low strain rate. Next, the strain under the loaded area increased as the tire shreds content was built up to 10 wt.%. Afterward, by increasing the weight percentage to 15%, the strains augmented again. Finally, by increasing the weight percentage of tire shreds with dimensions of 1\u0026times; 5 cm to 20%, the strains reached their maximum value at the slip surface.\u003c/p\u003e\n \u003cp\u003eThe PIV analysis results for the mixes containing tire shreds with dimensions of 2\u0026times;2 cm (Fig. \u003cspan class=\"InternalRef\"\u003e10\u003c/span\u003e) showed that by increasing the tire shreds content, the stress concentration reached its highest level in the mixture of soil and 20 wt.% of tire shreds with dimensions of 2\u0026times;2 cm.\u003c/p\u003e\n \u003cp\u003eIn mixes containing 5 wt.% of tire shreds, the wedge was formed with a small strain below the loading area. Next, with increasing the tire shreds content with dimensions of 2\u0026times;4 cm from 5 to 10 wt.%, the range of strains increased slightly. Increasing the weight percentage of tire shreds with dimensions of 2\u0026times;4 cm to 15% increased the strains. Finally, by increasing the weight percentage of tire shreds with dimensions of 2\u0026times;4 cm to 20 wt.%, again the strains were increased.\u003c/p\u003e\n \u003cp\u003eLike the trends that occurred in past experiments, by increasing tire shreds\u0026rsquo; content for tire shreds with a dimension of 2\u0026times;6, 2\u0026times;8, \u0026amp; 2\u0026times;10, the strains at the slip surface will be increased.\u003c/p\u003e\n \u003cp\u003eFigure 11 shows the Piv analysis results for the retaining wall made with virgin soil. The comparison shows that the strains formed at the slip surface of the retaining wall made with virgin soil and without any tire shred content were much more than those retaining walls made with mixes of tire shred and sand. A significant decrease in strains at the slip surface was seen by adding 5% wt tire shreds to the backfill of retaining walls. The depth of failure wedge was the same for all the tests, approximately. It means that adding tire shreds had not any significant effect on the depth of failure wedge in comparison with virgin soil. Also, It should be mentioned that the distance between the crown of the wall and the slip surface was identical in all tests, and tire shreds did not affect this parameter, too.\u003c/p\u003e\n \u003cp\u003eFrom the results of the PIV analysis, it can be concluded that by increasing the aspect ratio of tire shreds with a width of 1 cm from 1 to 2, at all weight percentages, an increase in strains on the slip surface will be seen. From Piv analysis, in tire shreds with a width of 1 cm, it was indicated that by increasing tire shreds aspect ratio the strains at slip surface will be incremented. This trend was also seen for tire shreds with a width of 2 cm.\u003c/p\u003e\n \u003cp\u003eComparing the PIV results for tests conducted on mixes with different tire shreds and horizontal wall displacement against the settlement induced below the wall shows that with increasing the tire shreds content of the mixes, the generated strains increase gradually.\u003c/p\u003e\n \u003cp\u003eThe maximum strain created in the slip surface occurred in a mix containing 20 wt.% of soil and tire shreds with dimensions of 2\u0026times;10 cm. Analysis of the PIV results also confirmed this finding. A comparison of PIV analysis and horizontal displacement results shown in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e also confirmed the agreement between PIV and horizontal wall displacement.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eIn this paper, the results of laboratory modeling are presented to investigate the effect of the aspect ratio and weight percentage of tire shreds on the embankment of retaining walls stabilized with multi-plate restraints. The particle image velocimetry (PIV) technique observed the wedge failure and evaluated the slip surface. The results are as follows:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e1. Resluts of direct shear tests show that internal friction angle and cohesion of the sand-tire shred mixtures will be incremented by increasing tire shreds aspect ratio in a constant weight percentage. Also, by increasing the tire shred\u0026apos;s weight percentage in a constant aspect ratio, the cohesion and internal friction angle of the sand-tire shred mixtures will be increased. It can be concluded that adding tire shreds with studied dimensions and weight percentages to sand improved the shear strength parameters of sand.\u003c/p\u003e\n\u003cp\u003e2. Increasing the weight percentage of tire shreds from 5% to higher percentages leads to increasing the load-bearing capacity of the retaining wall. The highest load-bearing capacity was related to the embankment with a mixture of 20 wt.% of tire shreds with dimensions of 2\u0026times;10 cm. At a constant weight percentage, increasing the aspect ratio of tire shreds in the mixture enhanced the load-bearing capacity of the wall. These were due to an increment in internal friction angle and cohesion of the sand-tire shred mixtures used as a replacement for the backfill virgin sandy soil in this study.\u003c/p\u003e\n\u003cp\u003e3. In all tests and at a constant aspect ratio and dimensions, the horizontal wall displacement increased by incrementing the weight percentage of the tire shreds. Also, it was concluded that by increasing the tire shreds aspect ratio in a constant weight percentage, the horizontal displacement of the wall will be increased.\u003c/p\u003e\n\u003cp\u003e4. The Piv analysis results show that by increasing tire shreds content in a constant aspect ratio, the strains at the slip surface would be incremented. It was found that the strains were increased at slip surface by increasing tire shreds aspect ratio in a constant weight percentage.\u003c/p\u003e\n\u003cp\u003e5. Results reveal that using tire shreds in the backfill of the retaining wall provides more bearing capacity than virgin soil alone. Also, it should be noted that walls made from mixes of tire shreds and sand had less horizontal displacement than a wall made with virgin soil.\u0026nbsp;From this point, it is received that adding the tire shreds to the wall backfill causes better performance of the wall both in the field of bearing capacity and horizontal displacement of the wall compared to the virgin soil without tire shreds.\u003c/p\u003e\n\u003cp\u003e6. Regarding the results of the experiments, it is suggested that instead of traditional rubber disposal methods such as incineration, accumulation, and unprincipled burial which have many risks and environmental pollution, tires be turned into tire shreds and used as fillers in earthen projects such as retaining walls and road embankments.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eFounding\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eConflicted of interest\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNot applicable\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eCompeting Interests\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eCode availability\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eNot applicable\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAvailable dataand materials\u003c/p\u003e\n\u003cp\u003eThe obtained data from experiments are in the result and discussion section, if you need the details of laboratory results, we can send an excel file\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eASTM, D.-. 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Waste Management, 26(3), 268\u0026ndash;276.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWhite, D., Take, W., \u0026amp; Bolton, M. (2003). Soil deformation measurement using particle image velocimetry (PIV) and photogrammetry. Geotechnique, 53(7), 619\u0026ndash;631.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWood, D. M. (2017). Geotechnical modelling. In U. London (Ed.). Taylor \u0026amp; Francis Group,: CRC press.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXiao, Y., Nan, B., \u0026amp; McCartney, J. S. (2019). Thermal conductivity of sand\u0026ndash;tire shred mixtures. Journal of Geotechnical and Geoenvironmental Engineering, 145(11), 06019012.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"tire shreds, scrap and recycled tires, aspect ratio, retaining wall, plate anchor, Particle Image Velocimetry (PIV)","lastPublishedDoi":"10.21203/rs.3.rs-1925499/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1925499/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eReusing scrap tires to save storage space or lower traditional disposal risks is among today's environmental challenges. Current, recycled tires are considered low-cost, lightweight materials to improve soils and retaining walls, backfills, and roadbeds. The present study investigated the effect of tire shred’s aspect ratio and weight percentage on the bearing capacity and displacement of the stabilized mechanical retaining wall with multi-plate anchors under static loading. To this end, sandy soils containing tire shreds with widths of 1 and 2 cm, aspect ratios of 1, 2, 3, 4, and 5, and weight percentages of 5, 10, 15, and 20% were examined. Also, direct shear tests were conducted for determining the shear strength parameters of the mixtures. The results demonstrated that adding more tire shreds increased bearing capacity. Also, it was found that by increasing the weight percentage of tire shreds in the mixture at a constant aspect ratio, the bearing capacity of the mixture increased. At a constant aspect ratio, the horizontal wall displacement incremented by increasing the weight percentage of the tire shreds. Furthermore, the wall's bearing capacity was enhanced at a constant weight percentage by increasing the aspect ratio of tire shreds. The results of Piv analysis show that by increasing tire shreds aspect ratio, the particle strains on the slip surface will be increased.\u003c/p\u003e","manuscriptTitle":"Influence Of Tire-Shreds' Aspect Ratio On Performance Of Mechanically Stabilized Retaining Walls","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-08-08 15:59:11","doi":"10.21203/rs.3.rs-1925499/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c27711bc-e921-480c-9394-e1228454d894","owner":[],"postedDate":"August 8th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-03-30T01:08:46+00:00","versionOfRecord":{"articleIdentity":"rs-1925499","link":"https://doi.org/10.1007/s13369-023-08184-y","journal":{"identity":"arabian-journal-for-science-and-engineering","isVorOnly":false,"title":"Arabian Journal for Science and Engineering"},"publishedOn":"2023-08-10 01:08:46","publishedOnDateReadable":"August 10th, 2023"},"versionCreatedAt":"2022-08-08 15:59:11","video":"","vorDoi":"10.1007/s13369-023-08184-y","vorDoiUrl":"https://doi.org/10.1007/s13369-023-08184-y","workflowStages":[]},"version":"v1","identity":"rs-1925499","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1925499","identity":"rs-1925499","version":["v1"]},"buildId":"-HB7Z8yhvgn0wM9Nzuekk","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}