Engineering Geological Characterization of Proposed Sabaloka Dam Site

Engineering Geological Characterization of Proposed Sabaloka Dam Site | 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Article Engineering Geological Characterization of Proposed Sabaloka Dam Site Mohmmed Hassan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6092009/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The Sabaloka dam is located at the Sabaloka igneous complex on the sixth cataract of the Nile, proposed for multi-purposes, mainly for hydro-power generation and irrigation in addition to help in minimizing the siltation for the Merwe dam to the north. Moreover, it will represent an excellent habitant for fisheries in the lake behind the dam. The study relied on field tests, well data, and analysis, in addition to the structural analysis of fractures in the examined site. Observing the results of drilling, the three boreholes are usually identical in lithology, where silt sands and conglomerates appear, but there is some difference in the depth of aggregation, in addition to the difference in the designation of rock quality (RQD), which decreases in borehole 403 in the left channel, due to the existence of Two sets of joints across the dextral fault. The proposed dam axis is located in the relatively less fractured Agglomeratic rocks. The main fracture trends are NW and NE directions and cut, respectively, the western and eastern flanks of the dam axis. Geology boreholes geotechnical analyzes River Nile Sabaloka dam Sudan Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 INTRODUTION The proposed dam is located at the Sabaloka igneous complex on the sixth cataract of the River Nile. The storage capacity of the proposed dam is about 4000 million cubic meters, its lake extends southward to about 15 km and the water level is expected to rise 6 to 10 meters. The Sabaloka dam is proposed for multi-purposes, mainly for hydro-power generation and irrigation in addition to help in minimizing the siltation for the Merwe dam to the north. Moreover, it will represent an excellent habitant for fisheries in the lake behind the dam. The main objective of this study Geotechnical treatments needed to identify the geotechnical properties of soil and rock foundations THE STUDY AREA The Sabaloka area is located in the southern part of the River Nile State between longitudes 32° – 32° 30" and latitudes 16° 15" – 16° 30" about 80 Km north of Khartoum (Fig. 1 ). This area is characterized by semi desert climatic conditions with average annual rainfalls range between 50–100 mm. The highest daily mean temperature is about 43˚C during the summer period from May to October, and the lowest mean temperature is about 16˚C during winter period from December to February. The Sabaloka area being one of the most important Pre-Cambrian exposure in Sudan, attracted the interest of may geologists such as; Delany ( 1958 ), Kroner et al ( 1987 ), Dawoud & Sadig ( 1988 ) and Almond & Ahmed ( 1993 ) to study different geological aspects of this area. Geologically, the area forms an inlier that consists of different type of rocks ranging from metamorphic (Gneiss and migmatites) through igneous (Sabaloka igneous complex) to sedimentary (Cretaceous sandstone). It represents a continental slope of the ancient continent during the Pan African time, Kroner et al. ( 1987 ). By early Paleozoic time the basement had been tectonically stabilized and reduced by erosion to a peneplain. The igneous activity; exemplified by the Sabaloka Igneous Complex is built up of felsic volcanoes which rise above the gneissose peneplain. The Sabaloka igneous plateau is consisted of basaltic lavas, agglomerate, rhyolite and ignimbrite, (Fig. 2 ). Tectonic Setting The Sabaloka rocky region of the Precambrian rocks is situated near the northeastern margin of ancient Africa, only a part of an enormous super continental margin orogenic belt named East Africa Orogeny (EAO) (Stern, 1994). The Ophiolites, granulite, and structures of the EAO are fossil fragments of a Neoproterozoic Wilson cycle, representing the opening and closing of an ocean basin that lay between the older crustal blocks of East and West Gondwanaland (Stern, 1994). The Wilson cycle of the EAO begins with rifting. The evidence for rifting may be preserved in sedimentary successions in the EAO that have been interpreted as a passive margin (Krӧner et al., 1987). Many of these collisions were between the arcs, as the oceanic crust between them was subducted. Still, a few collisions involved the addition of arcs and arc-complexes and continental micro-plates to the African margin. (Almond et al., 1993). The collisions led to low-grade metamorphic facies in the Nubian Arabian Shield (ANS) increasing in the grade of metamorphism toward the west of the Bayouda Desert and reaching a maximum in the Sabaloka area (Dawoud and Sadig, 1988 ). The sediments from Sudan were metamorphosed into granulite facies located in Sabaloka inlier at about 720 Ma (Krӧner et al., 1987). The crustal thickening produced pressures of about 6 to 8 Kbar, and temperatures in a range between 600–800 ˚ C (Dawoud and Dobrik, 1993) indicate the metamorphism in the deep- seated root of this continental crust with depth between 20–30 Km, which led to metamorphose that complex rocks of the old continental shelf in this depth at granulite facies. The Sabaloka granulite facies metamorphism, dated at about 700 Ma by Krӧner et al. (1987) may have taken place in the root zone of an island arc at about this time and in a dry environment. Also (Küster et al. 2008) dated by the geochronological and isotopic study of granitoid rocks from the eastern boundary of the Saharan Metacraton, indicate that the Bayuda Desert and Sabaloka region records orogenic events starting in the early Neoproterozoic (920 − 900 Ma: Bayudian event) and ending during late Pan African times (ca. 600–580 Ma). This age is similar to the Mozambique belt, which extends northward to include the Sabaloka area (Krӧner et al., 1987). The uplifting of granulite terrane was accompanied by hydration and retrogression under amphibolite facies, the condition that formed gneiss and migmatite rocks. The scale time is evident at Sabaloka between the granulite facies metamorphism 720Ma and retrogression migmatites possibly subsequent to uplifting 570Ma (Krӧner et al., 1987). This conversion of many dry granulite to amphibolite facies gneisses, which occurred about 150 Ma later, involved an abundance of hydrous solutions, and introduction of water into rocks hot dry rock caused extensive partial melting (Almond et al, 1993). This resulted in migmatization and the formation of small granite plutons, like Ban Gadeed, Babados, Es Suleik, and Abu Gedium. These events may have accompanied accretion of the arcs, and are assigned to the end of the Precambrian (Krӧner et al., 1987). The strike-slip tectonic movement of Ban Gadeed-Gamarab Shear Zone (BGSZ) which affected the Precambrian rocks of Sabaloka inlier is indicated by Ban Gadeed interfolial fold of Z- shape, and porphyroclasts of feldspar and quartz of augen gneiss, and miner interfolial folds in Al Gamarab area. Also, Abu Geidum shear (P-shear zone) supports that this shear is a dextral ductile shear zone. This horizontal tectonic movement may have occurred after the emplacement of older granites of Sabaloka inlier, and before the Abu Tulieh, Sabaloka, and Sileitat Es-Sufur igneous complexes, because the shear has not affected these igneous complexes. (Elyas, 2016 ). Tectonic stability was, however,locally punctuated by outbursts of igneous activity, which, at long intervals, built up felsic volcanoes risingabove the gneissose peneplain. The positions of these volcanoes are now marked by younger granite complexes, of which there are over 100 in Sudan alone (Vail, 1985 ). At Sabaloka inlier, the igneous activities are different in ages recently defined by isotope dating of the complexes of Tuleih, the Cauldron complex of Sabaloka, and Sileitat Es-Sufur (Almond et al., 1980). The most prominent post-Cretaceous structure in the Sabaloka area is the Umm Marahik fault and its associated transtensional basins. The principal displacement on this fault is recorded by a 2 km dextral shift of the sub-vertical structures of the Cauldron complex ring-fracture zone (Almond et al., 1980). Rejuvenating old fracture may have a bearing on Ban Gadeed-Gamarab Shear Zone (BGSZ) (Elyas,2016). A part from the E-W strike-slip faults, there are also several normal faults of small throw trending approximately N-S. Several of these faults can be seen offsetting the Nubian basal unconformity to the S and SE of Ban Gadeed (Almond et al., 1980) 2.1 Linear structures mapping The term lineaments have been used in the literature to elect different meanings. It has been applied to the orientation of natural as well as man-made features. The geology field lineaments indicate shear zones, fold axial traces, joints, fractures, faults, dykes, streams, or layering. Terrain-related lineaments might occur as straight, curvilinear, parallel, or en-echelon patterns and are generally related to fracture systems, discontinuity planes, fault traces, and shear zones, the manifestation of the lineaments is dependent on the scale of the observation and dimensions involved (Gupta, 2003). The structural analysis of lineaments is an essential step in acquiring basic knowledge about the structural evolution of an area. In the present study a Gram-Schmidt pan- sharpen image together with the spatially filtered images have been used within the GIS, where on- screen digitization has been conducted to draw a number of about 225 lineaments that range in length from 544 m to 2310 m Revised from Elsheikh. & Elsayed,(2010) Most outcrops of rocks exhibit many fractures that shows very small or unobservable displacement normal to their surface. Not all fractures in volcanic rock are of tectonic origin. They are mainly cooling joints whereby there is some fractures related to the post-cretaceous local faulting like Um Maraheik fault. Also, the derailing system in the area shown in lineament phenomena. From the following geological map (Fig. 3 ), it can be seen that the area forms an inlier that consists of different types of rocks ranging from metamorphic (gneiss and migmatites) through igneous (Sabaloka Igneous Complex; and basaltic lava, rhyolite, agglomerate, ignimbrite, and microgranite to sedimentary (Cretaceous sandstone). 2.2 Fractures Analysis Fractures are surfaces along which rocks or minerals have broken. Most outcrops of rocks exhibit many fractures that show very small or unobservable displacement normal to their surfaces, such fractures are called joints. Because the cohesion of the rocks is lost across fracture surfaces, they are considered to be planes of weakness that may affect the dam's efficiency. From this point of view, the fractures in the dam site's volcanic rocks were studied in detail. At the proposed dam site, the fractures in volcanic rocks are not of tectonic origin; instead, they are mainly cooling joints. Moreover, some fractures related to the post-Cretaceous local faulting, such as Um Maraheik fault. Um Maraheik fault is a rotational fault that bisects the cauldron complex with an E-W trend. The and most significant component of displacement is a dextral strike-slip movement of nearly 2 Km, with a significant element of down throw to the north. This vertical component increases westward fro Jebel Um Maraheik to reach a maximum value in the trans-tensional basin (graben) at the Elhugna area west of the Nile. According to gravity evidence, this basin maintains a vertical thickness of about 1.35 Km of sediment accumulations (Dawoud and Sadig, 1988 ). Structural setting Deformation is the change in an object's shape formed due to the application of a force or forces, or the action or process of changing in shape or distorting, primarily through applying pressure. When rocks deform in response to imposed stress, they exhibit strain, which is the differential change in size, shape, or volume of a material. Materials differ in their responses to stress, depending upon composition, temperature and confining pressure conditions, and strain rate. However, regardless of intrinsic degrees of brittle or ductile qualities, all strained materials pass through three successive stages of deformation: elastic, ductile, and fracture (failure, or brittle deformation) (Fig. 3 ). Provided that the strain rate is sufficiently slow to allow minerals to accommodate structurally, minerals can adjust to applied stresses by various mechanisms. 3.1 Primary Structures in the Study area Primary structures result from processes that form the rocks and do not relate to tectonic movements or deformations. The primary structure (S 0 ) in Precambrian basement rocks is unclear due to high deformation and metamorphism that formed the granoblastic texture of the polygonal mineral shape which obliterated old sediments' primary layering. Also, stigmatization cause becloud and deforming this primary structure (S 0 ). The primary structure (S 0 ) in sub-volcanic sediments is clear, because they are thermally metamorphosed. The old sediments of this unit are clastic, and it preserved the bedding of sediments which is an upward-fining sequence. The Trachybasalt and pyroclastic rocks of the volcanic Plateau appear with the columnar joints. Also, Jebal El-Rawian and Jebal Um Marahik of Cretaceous sediments are positioned on the gneisses rocks with unconformity plane, and they have bedding planes. The rhyolite of the cataract area contains the flow banding structures due to the viscosity of acidic magma, and ignimbrite has a eutaxitic texture. The eutectic texture is formed by gravity compaction of volcanic overload material during eruption processes. It flattened the pumice to a lense shape. The volcanic rocks of the Sabaloka complex are positioned on the gneisses with an unconformity plane, and this structure is secondary formed without deformation. (Elyas, 2016 ) 3.2 Secondary Structures and phases of Deformations These are four phases of deformation in the Precambrian rocks of Sabaloka inlier, beginning with the early and first progressive deformation (D1). It has three folding events the first of them is the upright tight fold (F1), the isoclinal recumbent fold is a second event (F2), and the similar recumbent fold is the last event (F3). The open concentric fold which is plunging to the East is the second phase of deformation (D2), and event four of folding (F4), the open fold which is plunging to the North is the third phase of deformation (D3), and event five folding. The ductile shear zone is the phase four of deformation (D4) whereas the interfolial fold which is formed due to deformation four is the six and the last event of folding in the region. The order of these phases of deformations and folding in the area will be described. The Drilling Work 4.1 Introduction Geotechnical work is usually performed to know the engineering geological properties of the site materials. This will help in the project design by using field tests (Stander Penetration Test, Permeability, Strength, rock Stability, Water Saturation, Porosity, and Layer thickness) performed in the borehole. Three boreholes were drilled at the proposed site by rotary drilling, and geotechnical analyzes, and the results were as shown below. 4.2 Classifications Of Some Discontinuity Features Discontinuity is any structural or geological feature that changes or alters the homogeneity of a rock, which may be technically joints, bedding planes, minor faults, or other surfaces of weakness, such as cleavage and schistosity planes. It excludes significant faults, since they are considered structural regions oftheir own. Discontinuities constitute a tremendous range, from structures of up to several kilometers in extent down to a few centimeters, ( Fig. 4 ) The two main groups are joints and weakness zones. These are described in the following: A Joint is a discontinuity plane of natural origin along which there has been no visible displacement. Joint is here used as a term for a break, fracture, or crack (Fig. 4 ) Singularity is a s mall weakness zone or a seam. A weakness zone is a part or zone in the ground in which the mechanical properties are significantly lower than the surrounding rock mass. Weakness zones can be faults, shears/shear zones, thrust zones, weak mineral layers, etc. Condition of discontinuities includes roughness of the discontinuity surfaces, their separation (distance between the surfaces), their length or continuity (persistence), weathering of the wall rock of the planes of weaknesses, and the infilling (gouge) leads to errors or inaccurate description/characterization and hence on the calculation results. Joint intercept is drill lengths of core pieces between the joint. This is seldom true joint set spacing, as joints of different sets are included in the measurement. In material. Some of these are classified into the following 3.2 several joints (jointing) Jointing is the occurrence of joint sets forming the system or pattern of joints and the amount or intensity of joints. Detailed jointing is the network of joints in the massifs between weakness zones. The degree of jointing/density of joints is the general term for the number of joints in a rock mass. This includes block size, joint set spacing, joint frequency, and rock quality designation (RQD). 3.3 joint spacing and degree of jointing Joints are found in specific, preferred directions as joint sets forming the jointing pattern. One to three prominent joint sets and one or more minor sets often occur; several individual or random joints may also be present. Joint set spacing is the distance between individual joints within a joint set. Joint spacing and average joint spacing are often used in describing and assessing rock masses. Note: the term "joint spacing" does not indicate whether it is the "joint intercept" or the "joint set spacing. "Thus, there is often much confusion related to the use of joint spacing, which often Table 1 Geomechanics Classification of Jointed rock masses, Bieniawski ( 1973 ) Item Class No and its description 1 2 3 4 5 Very good good Fair Poor Very poor 1 Rock quality RQD % 90–100 75–90 50–75 25–50 200 100–200 50–100 25–50 3m 1–3 m 0.3-1 m 50–300 mm < 50 mm 5 Separation of joints < 0.l mm 5mm 6 Continuity of joints Not continuous Not continuous Continuous no gouge Continuous with gouge Continuous with gouge 7 Ground water inflow (per 10m of adit) None None Slight 125 liters/min 8 Strike and dip orientations Very favorable Favorable Fair Unfavorable Very unfavorable 3.3 Borehole number (412) This drilling was drilled in 2018 with a total depth of 35 meters by rotary drilling on the island of Misikitab, to identify underground geological formations and engineering properties (Total depth 35.00 meters) . 3.3.1 Physical and Geotechnical Properties Of Agglomerate Start drill from 1m to 17.87m rocks are Silt and Sand with variation in color and a change in the rock's physical properties. The bottom of the well at a depth of 17.85meter formation is Silt described as Dark grey, wet, soft, and with low plasticity. At a depth of 17.85 meters to 35meter, rock is the Basement (Agglomerate ). Color : Reddish brown. Grain : Coarse-grained Hardness : Massive Support : Grain supported Sorting : Poorly sorted Granular : Composed welded angular to sub-angular fragment, mainly rhyolite. 3.3.2 Engineering Properties of Agglomerate Weathering : Variation from Fresh to Slightly weathering Strength : Range from very low to highly strength related to depth RQD : 80%-100% Fresh water return : 0%-20% 3.3.3 Joint Characteristics The angle of the dip: is 45degree Shape : Irregular Roughness : Rough Coating : Calcite / Iron oxid e Spacing : Close 3.4 Borehole number (403) This well is a drill with a (total depth of 61.10 meters ) Start Sand is dominate rock with a thin layer of Silt. 3.4.1 first layer (Sand) describes as follows: Color : variation in color Grain : Fine to Coarse grain Shape : Sub-rounded to angular Graded : Poorly grad Homogeneity : Homogenous rock Composition : Composed of sand and feldspar 3.4.2 Second layer ( Silt) In-depth 16meter to 19meter rock is composed of minor Sand, minor Clay, and trace Gravel, described as: Color : Dark grey Moisture : Wet Hardness : Soft Plasticity : Medium 3.4.3 Third layer ( Sand) at 19meter to 56.10meter, describe as: Color : variation in color Grain : Fine to Coarse grain Shape : sub rounded to angular Graded : Poorly grad Homogeneity : Homogenous rock 3.4.4 Basement (Agglomerate rock) at 56.10meter to 61.10meter describe as: Color : Reddish brown. Grain : Coarse-grained Hardness : Massive Support : Grain supported Texture : Heterolithc Sorting : Poorly sorted Granular : Composed welded angular to sub-angular fragment, mainly rhyolite. 3.4.5 Engineering Properties of Agglomerate Weathering : Slightly weathering along the joint plane, spacing fracture 7mete along a joint plane by drilling Strength : Highly strength RQD : 15%- 89% Fresh water return % : 99% 3.4.6 Joint Characteristics: The angle of dip : 10–60 degrees Shape : Irregular Roughness : Rough Coating : Kaolinite / Calcite Spacing : very wide, i.e. more than 2 meters 3.5 Borehole number 149 ( Total depth 50.30meter) 3.5.1 first layer (Silt) is described as: Color : Dark grey Moisture : Wet Hardness : Soft Plasticity : Low plasticity 3.5.2 Second layer (Sand) founds in 2.70meter to 45.30meter and describes as: Color : dark grey to grey Grain : Fine to Coarse grain with some silt Shape : Sub-rounded to angular Graded : Poorly graded Homogeneity : Homogenous rock Composition : Quartz & Feldspar Grain shape : subrounded to subangular 3.5.3 Basement (Agglomerate rock ) at 45.30meter to 50.30meter describe as: Color : Reddish brown. Grain : Coarse-grained Hardness : Massive Support : Grain supported Texture : Heterolithc texture Sorting : Poorly sorted Granular : Welded angular to sub- angular fragment, mainly rhyolite and part of ignimbrite. 3.5.4 Engineering Properties of Agglomerate Weathering : Slightly weathering along the joint plane Strength : Highly strength RQD : 46%- 100% Fresh water return : 95% − 99% 3.5.5 Joint Characteristics Angle of dip : 0.0–10 degrees Shape : Irregular Roughness : Rough Coating : Kaolinite / Calcite and Iron oxide Spacing : very wide, i.e. more than 2 meters 3.6 Summery of Drilling Results The drill borehole at the study area can identification of geological characteristics and engineering properties of the ground by knowing the structures and stability with types of joint characteristics that are summarized in Table 2 showing the orientation, material filling, degree or spacing and all of this information can help to identification the characteristic of the basements and which stable area for a building project, subsurface layers various into sand and silt formation with basement rock type is Agglomerate. The selection of three boreholes is based on the location of the dam, and it surveyed the area of the project with given complete information at. That we observation the ground of the three boreholes is typically matched but there are some different in the thickness of a layer such as Agglomerate in the borehole number 412 is more than other, and it found at shallow while in the other borehole is found deep in the bottom it with thickness 5meter and in 412 is 50% of total depth is Agglomerate and sediment formation in top Sand, and Silt formation at drilling we test the strength of rock during drilling and used SPT test with permeability and joint characteristic to measurement the engineering properties of rock and that gives good evidence of the study area with complete data concerned to project, the drilling borehole by rotary rig with geotechnical engineering method and test. Table 2 Correlations between boreholes No. 403, 412 &149 Location Description Left of Spill way channel Misikitab island Right of Spillway Channel Borehole number 403 412 149 Total depth 61.10meter 35.00meter 50.30meter Rock types sand / silt agglomerate sand / silt agglomerate sand / silt agglomerate Agglomerate depth 56.10 meter 17.85 meter 45.50 meters Rock Quality Designation (RQD) 15% − 89% 80% − 100% 46% − 100% Basement Weathering fresh to slightly fresh to slightly fresh to slightly Joint Characteristics Angle of dip 10° − 60° 0.0° − 45° 0.0° − 10° Shape Irregular Irregular irregular Roughness Rough Rough rough Coating kaolinite /calcite/iron oxide calcite/iron oxide calcite/iron oxide Spacing very wide Close very wide Fresh water return 99% 0%-20% 95% − 99% The selection of three boreholes is based on the location of the dam, and it surveyed the area of the project with given complete information at. That we observation the ground of the three boreholes is typically matched but there are some different in the thickness of a layer such as Agglomerate in the borehole number 412 is more than other, and it found at shallow while in the other borehole is found deep in the bottom it with thickness 5meter and in 412 is 50% of total depth is Agglomerate and sediment formation in top Sand, and Silt formation at drilling we test the strength of rock during drilling and used SPT test with permeability and joint characteristic to measurement the engineering properties of rock and that gives good evidence of the study area with complete data concerned to project, the drilling borehole by rotary rig with geotechnical engineering method and test. CONCLUSION AND RECOMMENDATIONS The study was conducted to examine the suitability of the selected site for the proposed hydro-power dam that located on the River Nile at about 80 km north of Khartoum town. The site is located at the narrow gorge of the River Nile on the volcanic plateau that mainly occupied by acid volcanic rocks characterized by highly jointed rocks. The main fractures trends are in NW and NE that need to be considered during the dam implementation. The dam axis is located on the relatively less fractured Agglomeratic rocks, three borehole is typically matched but there are some different into the Depth of Basement (Agglomerate) This study has recommended that This research work suggested that during construction phase the engineering geologist should take worry of horizontal lithological variation by taking References Almond DC, Ahmed F (1993) Field guide to the geology of the Sabaloka Inlier, Central Sudan. Khartoum University Press, Khartoum Sudan Almond DC (1980) : Precambrian events at Sabaloka, near Khartoum, and their significance in the chronology of the basement complex of North-East Africa, Precambrian Research, Volume 13, Issue 1, September 1980,Pages 43–47, 51–62 Bieniawski ZT (1973), : Engineering Classification of Jointed Rock Masses, Paper in THE CIVIL ENGINEER in South Africa - December 1973 pages 335–343 Dawoud AS, Dobric B (eds) (1993) : PT Condition of Pan African Granulite Facies Metamorphism in Sabaloka Inlier North of Khartoum, Sudan. Geo Sci.Res. In North East (ed) Thoreweihe and Schandelemeier. (Stern, 1994) Dawoud AS, Sadig AA (1988) Structural and Gravity Evidence of an Uplifted Pan African Terrain in Sabaloka Inlier. J Afr Earth Sci 7:787–794 Delany FM (1958) Observations on the Sabaloka Series of Sudan, Transactions of the geology Society of South Africa. 61:111–124 Elyas M (2016) : The Geology and Structure of the Precambrian Basement Rocksof the Sabaloka Inlier, North Khartoum, Sudan: Remote Sensing and Petrological Approaches. M. Sc. Thesis, Al Neelain University Kroner A, Stern RJ, Dawoud AS, Compston W, Reischmann T (1987) The Pan- African continental margin in northeastern Africa: evidence from the geochronological study of granulite at Sabaloka, Sudan. Earth Planet Sci Lett 85:91–104 Palmström (1995) : Design and Construction of underground Structures, New Delhi, Norwegian Geotechnical Institute 23–25 February 1995 Vail JR (1985) : Alkaline ring complexes in Sudan. Dept. Geol. Portsmouth Polytechnic, U.K. Vol.13, 51–59. Additional Declarations The authors declare potential competing interests as follows: The author whose name is listed immediately below certify that he have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript. Author name: Mohammed Ahmed Mohammed Hassan Supplementary Files supplementarymaterial.pdf Manuscript in PDF format DAMSITEINVESTIGATION.jpg A model of the locations of the poreholes from which samples were taken on a map of the Sablouga area (author’s work) Cite Share Download PDF Status: Posted 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-6092009","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":419776818,"identity":"0fb67a57-c073-4b7f-9d6f-bcfc1dbfad2f","order_by":0,"name":"Mohmmed Hassan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA30lEQVRIiWNgGAWjYJACZiDm4WdvPgCkJWSI0gDWItlzLAGkhYdoLQwGN3IMQDRhLboN/AcfF9RskzE4kPP51Y0aCx4G9sNHN+DTYnaAmdl4xrHbPJIHzm6zzjkGdBhPWtoNAlrYpHnYbvPwHezdZpzDBtQiwWNGSAv7b55/t3kYDvM8M875R5wWNmbetts8Asd4mB/nthGj5TCzsTRvH9AvPWxmzLl9EjxsBP1yvPHhZ55vt+355R8//pzzrU6On/3wMbxaIJECAWwSYBKvcnTdH0hRPQpGwSgYBSMHAAAiDUM9Z7WHzgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0009-0002-2057-0417","institution":"Sudan University of Science and Technology","correspondingAuthor":true,"prefix":"","firstName":"Mohmmed","middleName":"","lastName":"Hassan","suffix":""}],"badges":[],"createdAt":"2025-02-23 21:14:56","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":true,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-6092009/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6092009/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":77202801,"identity":"e84e72df-038c-48a2-9356-1bf9176603d6","added_by":"auto","created_at":"2025-02-26 07:42:52","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":116158,"visible":true,"origin":"","legend":"\u003cp\u003eLocation map of the study area\u003c/p\u003e","description":"","filename":"image1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/e1ef5d435c1664ae5ceb4abb.jpeg"},{"id":77202802,"identity":"2a7eceeb-4914-4907-9b4f-7b7f1baaf4bd","added_by":"auto","created_at":"2025-02-26 07:42:53","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":91613,"visible":true,"origin":"","legend":"\u003cp\u003eGeological sketch map of Sabaloka igneous complex\u003c/p\u003e","description":"","filename":"image2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/f3fc476bfd540f075073a21d.jpeg"},{"id":77202803,"identity":"a80fe0d2-8496-40ba-8324-0892b0b447cd","added_by":"auto","created_at":"2025-02-26 07:42:53","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":102523,"visible":true,"origin":"","legend":"\u003cp\u003eLinear Map of the Sabaloka Volcanic Plateau. With the projection showing the predominant direction of those fractures\u003c/p\u003e","description":"","filename":"image3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/b4058ca2d11d9c3c6b5be6da.jpeg"},{"id":77203094,"identity":"fb6adf26-7310-4cbf-a5b9-b6238b8e9ba6","added_by":"auto","created_at":"2025-02-26 07:50:53","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":108371,"visible":true,"origin":"","legend":"\u003cp\u003eRose Diagram shows the main trends of fractures in the Sabaloka Plateau.\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/5166107d0e5500b116853d8f.png"},{"id":77202806,"identity":"56a9d511-a0f3-43e3-ae4c-50b2e1a89e1f","added_by":"auto","created_at":"2025-02-26 07:42:53","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":42311,"visible":true,"origin":"","legend":"\u003cp\u003eThe main types of discontinuities according to size (revised from Palmström, 1995)\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/911a981d477eff49a5cc691d.png"},{"id":77203116,"identity":"06e9ed3e-0128-466d-bc66-e86b95bd9ac0","added_by":"auto","created_at":"2025-02-26 07:50:54","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1081429,"visible":true,"origin":"","legend":"\u003cp\u003eStrength diagram of jointed rock masses, Bieniawski (1973)\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/4e10c9bc3e7dec418765bc73.png"},{"id":77202812,"identity":"ed4f06f6-f590-46cd-8c44-07d236f758fd","added_by":"auto","created_at":"2025-02-26 07:42:53","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":142495,"visible":true,"origin":"","legend":"\u003cp\u003eLithological profile showing the rock layers in borehole 412\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/208504aa054a50264cb7b9e1.png"},{"id":77202823,"identity":"2f3b1c4a-11f3-47ef-9193-0ea5afffd21e","added_by":"auto","created_at":"2025-02-26 07:42:53","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":179144,"visible":true,"origin":"","legend":"\u003cp\u003eLithological profile showing the rock layers in borehole 403\u003c/p\u003e","description":"","filename":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/ca69dcf9081f946de2b78ec5.png"},{"id":77202805,"identity":"06f26e31-c8dc-4195-b57d-4f4fb1ac3dfc","added_by":"auto","created_at":"2025-02-26 07:42:53","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":120144,"visible":true,"origin":"","legend":"\u003cp\u003eLithological profile showing the rock layers in borehole 149\u003c/p\u003e","description":"","filename":"image9.png","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/a31ff816a217d697c9136ebd.png"},{"id":77204265,"identity":"9cdafc24-162b-45b5-b79d-08df4f29a154","added_by":"auto","created_at":"2025-02-26 08:06:58","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3442406,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/a240d4dc-8976-4b46-88dd-96bf98fd3b4c.pdf"},{"id":77203092,"identity":"523ffd85-bed7-4810-adf3-97489de708ed","added_by":"auto","created_at":"2025-02-26 07:50:53","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":917897,"visible":true,"origin":"","legend":"\u003cp\u003eManuscript in PDF format\u003c/p\u003e","description":"","filename":"supplementarymaterial.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/af68ea03b1002c77a5afd5b8.pdf"},{"id":77202808,"identity":"19ab121e-f1d5-4961-93ad-76c3fe499a4c","added_by":"auto","created_at":"2025-02-26 07:42:53","extension":"jpg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":174816,"visible":true,"origin":"","legend":"\u003cp\u003eA model of the locations of the poreholes from which samples were taken on a map of the Sablouga area (author’s work)\u003c/p\u003e","description":"","filename":"DAMSITEINVESTIGATION.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6092009/v1/2a0061f086840d098c9e8319.jpg"}],"financialInterests":"The authors declare potential competing interests as follows: The author whose name is listed immediately below certify that he have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.\n\n\nAuthor name: Mohammed Ahmed Mohammed Hassan ","formattedTitle":"\u003cp\u003eEngineering Geological Characterization of Proposed Sabaloka Dam Site\u003c/p\u003e","fulltext":[{"header":"INTRODUTION","content":"\u003cp\u003eThe proposed dam is located at the Sabaloka igneous complex on the sixth cataract of the\u003c/p\u003e \u003cp\u003eRiver Nile.\u003c/p\u003e \u003cp\u003eThe storage capacity of the proposed dam is about 4000\u0026nbsp;million cubic meters, its lake extends southward to about 15 km and the water level is expected to rise 6 to 10 meters.\u003c/p\u003e \u003cp\u003eThe Sabaloka dam is proposed for multi-purposes, mainly for hydro-power generation and irrigation in addition to help in minimizing the siltation for the Merwe dam to the north. Moreover, it will represent an excellent habitant for fisheries in the lake behind the dam.\u003c/p\u003e \u003cp\u003eThe main objective of this study Geotechnical treatments needed to identify the geotechnical properties of soil and rock foundations\u003c/p\u003e"},{"header":"THE STUDY AREA","content":"\u003cp\u003eThe Sabaloka area is located in the southern part of the River Nile State between longitudes 32° – 32° 30\" and latitudes 16° 15\" – 16° 30\" about 80 Km north of Khartoum (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). This area is characterized by semi desert climatic conditions with average annual rainfalls range between 50–100 mm. The highest daily mean temperature is about 43˚C during the summer period from May to October, and the lowest mean temperature is about 16˚C during winter period from December to February.\u003c/p\u003e \u003cp\u003eThe Sabaloka area being one of the most important Pre-Cambrian exposure in Sudan, attracted the interest of may geologists such as; Delany (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1958\u003c/span\u003e), Kroner et al (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1987\u003c/span\u003e), Dawoud \u0026amp; Sadig (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1988\u003c/span\u003e) and Almond \u0026amp; Ahmed (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1993\u003c/span\u003e) to study different geological aspects of this area.\u003c/p\u003e \u003cp\u003eGeologically, the area forms an inlier that consists of different type of rocks ranging from metamorphic (Gneiss and migmatites) through igneous (Sabaloka igneous complex) to sedimentary (Cretaceous sandstone). It represents a continental slope of the ancient continent during the Pan African time, Kroner et al. (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1987\u003c/span\u003e). By early Paleozoic time the basement had been tectonically stabilized and reduced by erosion to a peneplain. The igneous activity; exemplified by the Sabaloka Igneous Complex is built up of felsic volcanoes which rise above the gneissose peneplain. The Sabaloka igneous plateau is consisted of basaltic lavas, agglomerate, rhyolite and ignimbrite, (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \n\n \n\n \u003cp\u003e \u003c/p\u003e"},{"header":"Tectonic Setting","content":"\u003cp\u003eThe Sabaloka rocky region of the Precambrian rocks is situated near the northeastern margin of ancient Africa, only a part of an enormous super continental margin orogenic belt named East Africa Orogeny (EAO) (Stern, 1994). The Ophiolites, granulite, and structures of the EAO are fossil fragments of a Neoproterozoic Wilson cycle, representing the opening and closing of an ocean basin that lay between the older crustal blocks of East and West Gondwanaland (Stern, 1994). The Wilson cycle of the EAO begins with rifting. The evidence for rifting may be preserved in sedimentary successions in the EAO that have been interpreted as a passive margin (Krӧner et al., 1987). Many of these collisions were between the arcs, as the oceanic crust between them was subducted. Still, a few collisions involved the addition of arcs and arc-complexes and continental micro-plates to the African margin. (Almond et al., 1993).\u003c/p\u003e\u003cp\u003eThe collisions led to low-grade metamorphic facies in the Nubian Arabian Shield (ANS) increasing in the grade of metamorphism toward the west of the Bayouda Desert and reaching a maximum in the Sabaloka area (Dawoud and Sadig, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1988\u003c/span\u003e). The sediments from Sudan were metamorphosed into granulite facies located in Sabaloka inlier at about 720 Ma (Krӧner et al., 1987). The crustal thickening produced pressures of about 6 to 8 Kbar, and temperatures in a range between 600–800 ˚ C (Dawoud and Dobrik, 1993) indicate the metamorphism in the deep- seated root of this continental crust with depth between 20–30 Km, which led to metamorphose that complex rocks of the old continental shelf in this depth at granulite facies. The Sabaloka granulite facies metamorphism, dated at about 700 Ma by Krӧner et al. (1987) may have taken place in the root zone of an island arc at about this time and in a dry environment. Also (Küster et al. 2008) dated by the geochronological and isotopic study of granitoid rocks from the eastern boundary of the Saharan Metacraton, indicate that the Bayuda Desert and Sabaloka region records orogenic events starting in the early Neoproterozoic (920 − 900 Ma: Bayudian event) and ending during late Pan African times (ca. 600–580 Ma). This age is similar to the Mozambique belt, which extends northward to include the Sabaloka area (Krӧner et al., 1987).\u003c/p\u003e\u003cp\u003eThe uplifting of granulite terrane was accompanied by hydration and retrogression under amphibolite facies, the condition that formed gneiss and migmatite rocks. The scale time is evident at Sabaloka between the granulite facies metamorphism 720Ma and retrogression migmatites possibly subsequent to uplifting 570Ma (Krӧner et al., 1987). This conversion of many dry granulite to amphibolite facies gneisses, which occurred about 150 Ma later, involved an abundance of hydrous solutions, and introduction of water into rocks hot dry rock caused extensive partial melting (Almond et al, 1993). This resulted in migmatization and the formation of small granite plutons, like Ban Gadeed, Babados, Es Suleik, and Abu Gedium. These events may have accompanied accretion of the arcs, and are assigned to the end of the Precambrian (Krӧner et al., 1987).\u003c/p\u003e\u003cp\u003eThe strike-slip tectonic movement of Ban Gadeed-Gamarab Shear Zone (BGSZ) which affected the Precambrian rocks of Sabaloka inlier is indicated by Ban Gadeed interfolial fold of Z- shape, and porphyroclasts of feldspar and quartz of augen gneiss, and miner interfolial folds in Al Gamarab area. Also, Abu Geidum shear (P-shear zone) supports that this shear is a dextral ductile shear zone. This horizontal tectonic movement may have occurred after the emplacement of older granites of Sabaloka inlier, and before the Abu Tulieh, Sabaloka, and Sileitat Es-Sufur igneous complexes, because the shear has not affected these igneous complexes. (Elyas, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Tectonic stability was, however,locally punctuated by outbursts of igneous activity, which, at long intervals, built up felsic volcanoes risingabove the gneissose peneplain. The positions of these volcanoes are now marked by younger granite complexes, of which there are over 100 in Sudan alone (Vail, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1985\u003c/span\u003e). At Sabaloka inlier, the igneous activities are different in ages recently defined by isotope dating of the complexes of Tuleih, the Cauldron complex of Sabaloka, and Sileitat Es-Sufur (Almond et al., 1980).\u003c/p\u003e\u003cp\u003eThe most prominent post-Cretaceous structure in the Sabaloka area is the Umm Marahik fault and its associated transtensional basins. The principal displacement on this fault is recorded by a 2 km dextral shift of the sub-vertical structures of the Cauldron complex ring-fracture zone (Almond et al., 1980). Rejuvenating old fracture may have a bearing on Ban Gadeed-Gamarab Shear Zone (BGSZ) (Elyas,2016). A part from the E-W strike-slip faults, there are also several normal faults of small throw trending approximately N-S. Several of these faults can be seen offsetting the Nubian basal unconformity to the S and SE of Ban Gadeed (Almond et al., 1980)\u003c/p\u003e\u003ch3\u003e2.1 Linear structures mapping\u003c/h3\u003e\u003cp\u003eThe term lineaments have been used in the literature to elect different meanings. It has been applied to the orientation of natural as well as man-made features. The geology field lineaments indicate shear zones, fold axial traces, joints, fractures, faults, dykes, streams, or layering. Terrain-related lineaments might occur as straight, curvilinear, parallel, or en-echelon patterns and are generally related to fracture systems, discontinuity planes, fault traces, and shear zones, the manifestation of the lineaments is dependent on the scale of the observation and dimensions involved (Gupta, 2003). The structural analysis of lineaments is an essential step in acquiring basic knowledge about the structural evolution of an area.\u003c/p\u003e\u003cp\u003eIn the present study a Gram-Schmidt pan- sharpen image together with the spatially filtered images have been used within the GIS, where on- screen digitization has been conducted to draw a number of about 225 lineaments that range in length from 544 m to 2310 m\u003c/p\u003e\u003cp\u003eRevised from Elsheikh. \u0026amp; Elsayed,(2010) Most outcrops of rocks exhibit many fractures that shows very small or unobservable displacement normal to their surface. Not all fractures in volcanic rock are of tectonic origin. They are mainly cooling joints whereby there is some fractures related to the post-cretaceous local faulting like Um Maraheik fault. Also, the derailing system in the area shown in lineament phenomena.\u003c/p\u003e\u003cp\u003eFrom the following geological map (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e ), it can be seen that the area forms an inlier that consists of different types of rocks ranging from metamorphic (gneiss and migmatites) through igneous (Sabaloka Igneous Complex; and basaltic lava, rhyolite, agglomerate, ignimbrite, and microgranite to sedimentary (Cretaceous sandstone).\u003c/p\u003e\u003cp\u003e \u003c/p\u003e\u003ch3\u003e2.2 Fractures Analysis\u003c/h3\u003e\u003cp\u003eFractures are surfaces along which rocks or minerals have broken. Most outcrops of rocks exhibit many fractures that show very small or unobservable displacement normal to their surfaces, such fractures are called joints. Because the cohesion of the rocks is lost across fracture surfaces, they are considered to be planes of weakness that may affect the dam's efficiency. From this point of view, the fractures in the dam site's volcanic rocks were studied in detail.\u003c/p\u003e\u003cp\u003eAt the proposed dam site, the fractures in volcanic rocks are not of tectonic origin; instead, they are mainly cooling joints. Moreover, some fractures related to the post-Cretaceous local faulting, such as Um Maraheik fault. Um Maraheik fault is a rotational fault that bisects the cauldron complex with an E-W trend. The and most significant component of displacement is a dextral strike-slip movement of nearly 2 Km, with a significant element of down throw to the north. This vertical component increases westward fro Jebel Um Maraheik to reach a maximum value in the trans-tensional basin (graben) at the Elhugna area west of the Nile. According to gravity evidence, this basin maintains a vertical thickness of about 1.35 Km of sediment accumulations (Dawoud and Sadig, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1988\u003c/span\u003e).\u003c/p\u003e"},{"header":"Structural setting","content":"\u003cp\u003eDeformation is the change in an object's shape formed due to the application of a force or forces, or the action or process of changing in shape or distorting, primarily through applying pressure. When rocks deform in response to imposed stress, they exhibit strain, which is the differential change in size, shape, or volume of a material. Materials differ in their responses to stress, depending upon composition, temperature and confining pressure conditions, and strain rate. However, regardless of intrinsic degrees of brittle or ductile qualities, all strained materials pass through three successive stages of deformation: elastic, ductile, and fracture (failure, or brittle deformation) (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Provided that the strain rate is sufficiently slow to allow minerals to accommodate structurally, minerals can adjust to applied stresses by various mechanisms.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003e3.1 Primary Structures in the Study area\u003c/h3\u003e\n\u003cp\u003ePrimary structures result from processes that form the rocks and do not relate to tectonic movements or deformations. The primary structure (S\u003csub\u003e0\u003c/sub\u003e) in Precambrian basement rocks is unclear due to high deformation and metamorphism that formed the granoblastic texture of the polygonal mineral shape which obliterated old sediments' primary layering.\u003c/p\u003e \u003cp\u003eAlso, stigmatization cause becloud and deforming this primary structure (S\u003csub\u003e0\u003c/sub\u003e). The primary structure (S\u003csub\u003e0\u003c/sub\u003e) in sub-volcanic sediments is clear, because they are thermally metamorphosed. The old sediments of this unit are clastic, and it preserved the bedding of sediments which is an upward-fining sequence.\u003c/p\u003e \u003cp\u003eThe Trachybasalt and pyroclastic rocks of the volcanic Plateau appear with the columnar joints. Also, Jebal El-Rawian and Jebal Um Marahik of Cretaceous sediments are positioned on the gneisses rocks with unconformity plane, and they have bedding planes. The rhyolite of the cataract area contains the flow banding structures due to the viscosity of acidic magma, and ignimbrite has a eutaxitic texture. The eutectic texture is formed by gravity compaction of volcanic overload material during eruption processes. It flattened the pumice to a lense shape. The volcanic rocks of the Sabaloka complex are positioned on the gneisses with an unconformity plane, and this structure is secondary formed without deformation. (Elyas, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2016\u003c/span\u003e)\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Secondary Structures and phases of Deformations\u003c/h2\u003e \u003cp\u003eThese are four phases of deformation in the Precambrian rocks of Sabaloka inlier, beginning with the early and first progressive deformation (D1). It has three folding events the first of them is the upright tight fold (F1), the isoclinal recumbent fold is a second event (F2), and the similar recumbent fold is the last event (F3). The open concentric fold which is plunging to the East is the second phase of deformation (D2), and event four of folding (F4), the open fold which is plunging to the North is the third phase of deformation (D3), and event five folding. The ductile shear zone is the phase four of deformation (D4) whereas the interfolial fold which is formed due to deformation four is the six and the last event of folding in the region. The order of these phases of deformations and folding in the area will be described.\u003c/p\u003e \u003c/div\u003e"},{"header":"The Drilling Work","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n\u003ch2\u003e4.1 Introduction\u003c/h2\u003e\n\u003cp\u003eGeotechnical work is usually performed to know the engineering geological properties of the site materials. This will help in the project design by using field tests (Stander Penetration Test, Permeability, Strength, rock Stability, Water Saturation, Porosity, and Layer thickness) performed in the borehole.\u003c/p\u003e\n\u003cp\u003eThree boreholes were drilled at the proposed site by rotary drilling, and geotechnical analyzes, and the results were as shown below.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n\u003ch2\u003e4.2 Classifications Of Some Discontinuity Features\u003c/h2\u003e\n\u003cp\u003e\u003cem\u003eDiscontinuity\u003c/em\u003e is any structural or geological feature that changes or alters the homogeneity of a rock, which may be technically joints, bedding planes, minor faults, or other surfaces of weakness, such as cleavage and schistosity planes. It excludes \u003cspan class=\"Underline\"\u003esignificant\u003c/span\u003e faults, since they are considered structural regions oftheir own.\u003c/p\u003e\n\u003cdiv class=\"BlockQuote\"\u003e\n\u003cp\u003eDiscontinuities constitute a tremendous range, from structures of up to several kilometers in extent down to a few centimeters, ( Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e) The two main groups are joints and weakness zones. These are described in the following:\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cem\u003eA Joint\u003c/em\u003e is a discontinuity plane of natural origin along which there has been no visible displacement. Joint is here used as a term for a break, fracture, or crack (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cem\u003eSingularity\u003c/em\u003e is a \u003cem\u003es\u003c/em\u003emall weakness zone or a seam.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cem\u003eA weakness zone\u003c/em\u003e is a part or zone in the ground in which the mechanical properties are significantly lower than the surrounding rock mass. Weakness zones can be faults, shears/shear zones, thrust zones, weak mineral layers, etc.\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eCondition of discontinuities includes roughness of the discontinuity surfaces, their separation (distance between the surfaces), their length or continuity (persistence), weathering of the wall rock of the planes of weaknesses, and the infilling (gouge)\u003c/p\u003e\n\u003cp\u003eleads to errors or inaccurate description/characterization and hence on the calculation results. Joint intercept is drill lengths of core pieces between the joint. This is seldom true joint set spacing, as joints of different sets are included in the measurement. In material. Some of these are classified into the following\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n\u003ch2\u003e3.2 several joints (jointing)\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eJointing is the occurrence of joint sets forming the system or pattern of joints and the amount or intensity of joints.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eDetailed jointing is the network of joints in the massifs between weakness zones.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003eThe degree of jointing/density of joints is the general term for the number of joints in a rock mass. This includes block size, joint set spacing, joint frequency, and rock quality designation (RQD).\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\n\u003ch2\u003e3.3 joint spacing and degree of jointing\u003c/h2\u003e\n\u003cp\u003eJoints are found in specific, preferred directions as joint sets forming the jointing pattern. One to three prominent joint sets and one or more minor sets often occur; several individual or random joints may also be present. Joint set spacing is the distance between individual joints within a joint set. Joint spacing and average joint spacing are often used in describing and assessing rock masses. Note: the term \"joint spacing\" does not indicate whether it is the \"joint intercept\" or the \"joint set spacing. \"Thus, there is often much confusion related to the use of joint spacing, which often\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eGeomechanics Classification of Jointed rock masses, Bieniawski (\u003cspan class=\"CitationRef\"\u003e1973\u003c/span\u003e)\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\u003ccolgroup\u003e\u003c/colgroup\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eItem\u003c/p\u003e\n\u003c/th\u003e\n\u003cth rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eClass No and its description\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e1\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e2\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e3\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e4\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003e5\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eVery good\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003egood\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eFair\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePoor\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eVery poor\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\u003eRock quality RQD %\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e90\u0026ndash;100\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e75\u0026ndash;90\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50\u0026ndash;75\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e25\u0026ndash;50\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;25\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\u003eWeathering\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eUnweathered\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSlightly weathered\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eModerately weathered\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eHighly weathered\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eCompletely weathered\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\u003eIntact rock strength, MPa\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;200\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e100\u0026ndash;200\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50\u0026ndash;100\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e25\u0026ndash;50\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;25\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\u003eSpacing of joints\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;3m\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u0026ndash;3 m\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.3-1 m\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50\u0026ndash;300 mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;50 mm\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\u003eSeparation of joints\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.l mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026lt;\u0026thinsp;0.l mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.1-1 mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e1\u0026ndash;5 mm\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;5mm\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\u003eContinuity of joints\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNot continuous\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNot continuous\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eContinuous no gouge\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eContinuous with gouge\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eContinuous with gouge\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\u003eGround water inflow (per 10m of adit)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eSlight\u0026thinsp;\u0026lt;\u0026thinsp;25 liters/min\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eModerate\u003c/p\u003e\n\u003cp\u003e25\u0026ndash;125 liters/min\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eHeavy\u0026thinsp;\u0026gt;\u0026thinsp;125 liters/min\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\u003eStrike and dip orientations\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eVery favorable\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eFavorable\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eFair\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eUnfavorable\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eVery unfavorable\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\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\n\u003ch2\u003e3.3 Borehole number (412)\u003c/h2\u003e\n\u003cp\u003eThis drilling was drilled in 2018 with a total depth of 35 meters by rotary drilling on the island of Misikitab, to identify underground geological formations and engineering properties (Total depth \u003cstrong\u003e35.00 meters)\u003c/strong\u003e.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\n\u003ch2\u003e3.3.1 Physical and Geotechnical Properties Of Agglomerate\u003c/h2\u003e\n\u003cp\u003eStart drill from 1m to 17.87m rocks are \u003cstrong\u003eSilt\u003c/strong\u003e and \u003cstrong\u003eSand\u003c/strong\u003e with variation in color and a change in the rock's physical properties.\u003c/p\u003e\n\u003cp\u003eThe bottom of the well at a depth of 17.85meter formation is Silt described as Dark grey, wet, soft, and with low plasticity.\u003c/p\u003e\n\u003cp\u003eAt a depth of 17.85 meters to 35meter, rock is the \u003cstrong\u003eBasement (Agglomerate\u003c/strong\u003e).\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eColor\u003c/strong\u003e: Reddish brown.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGrain\u003c/strong\u003e: Coarse-grained\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHardness\u003c/strong\u003e: Massive\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSupport\u003c/strong\u003e: Grain supported\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSorting\u003c/strong\u003e: Poorly sorted\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGranular\u003c/strong\u003e: Composed welded angular to sub-angular fragment, mainly rhyolite.\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\n\u003ch2\u003e3.3.2 Engineering Properties of Agglomerate\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eWeathering\u003c/strong\u003e: Variation from Fresh to Slightly weathering\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eStrength\u003c/strong\u003e: Range from very low to highly strength related to depth\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eRQD\u003c/strong\u003e: 80%-100%\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eFresh water return\u003c/strong\u003e: 0%-20%\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\n\u003ch2\u003e3.3.3 Joint Characteristics\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eThe angle of the dip: is\u003c/strong\u003e 45degree\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eShape\u003c/strong\u003e: Irregular\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eRoughness\u003c/strong\u003e: Rough\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eCoating\u003c/strong\u003e: Calcite / Iron oxid\u003cstrong\u003ee\u003c/strong\u003e\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSpacing\u003c/strong\u003e: Close\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\n\u003ch2\u003e3.4 Borehole number (403)\u003c/h2\u003e\n\u003cp\u003eThis well is a drill with a (total depth of \u003cstrong\u003e61.10 meters\u003c/strong\u003e)\u003c/p\u003e\n\u003cp\u003eStart Sand is dominate rock with a thin layer of Silt.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.1\u0026nbsp;first layer\u003c/strong\u003e (Sand) describes as follows:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eColor\u003c/strong\u003e: variation in color\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGrain\u003c/strong\u003e: Fine to Coarse grain\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eShape\u003c/strong\u003e: Sub-rounded to angular\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGraded\u003c/strong\u003e: Poorly grad\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHomogeneity\u003c/strong\u003e: Homogenous rock\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eComposition\u003c/strong\u003e: Composed of sand and feldspar\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cstrong\u003e3.4.2 Second layer (\u003c/strong\u003eSilt) In-depth 16meter to 19meter rock is composed of minor Sand, minor Clay, and trace Gravel, described as:\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eColor\u003c/strong\u003e: Dark grey\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eMoisture\u003c/strong\u003e: Wet\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHardness\u003c/strong\u003e: Soft\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003ePlasticity\u003c/strong\u003e: Medium\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.3\u003c/strong\u003e\u0026nbsp;\u003cstrong\u003eThird layer (\u003c/strong\u003eSand) at 19meter to 56.10meter, describe as:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eColor\u003c/strong\u003e: variation in color\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGrain\u003c/strong\u003e: Fine to Coarse grain\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eShape\u003c/strong\u003e: sub rounded to angular\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGraded\u003c/strong\u003e: Poorly grad\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHomogeneity\u003c/strong\u003e: Homogenous rock\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cstrong\u003e3.4.4 Basement\u003c/strong\u003e (Agglomerate rock) at 56.10meter to 61.10meter describe as:\u003cbr /\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eColor\u003c/strong\u003e: Reddish brown.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGrain\u003c/strong\u003e: Coarse-grained\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHardness\u003c/strong\u003e: Massive\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSupport\u003c/strong\u003e: Grain supported\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eTexture\u003c/strong\u003e: Heterolithc\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSorting\u003c/strong\u003e: Poorly sorted\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGranular\u003c/strong\u003e: Composed welded angular to sub-angular fragment, mainly rhyolite.\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.5 Engineering Properties of Agglomerate\u003c/strong\u003e\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eWeathering\u003c/strong\u003e: Slightly weathering along the joint plane, spacing fracture 7mete along a joint plane by drilling\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eStrength\u003c/strong\u003e: Highly strength\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eRQD\u003c/strong\u003e: 15%- 89%\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eFresh water return %\u003c/strong\u003e: 99%\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\n\u003ch2\u003e3.4.6 Joint Characteristics:\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eThe angle of dip\u003c/strong\u003e: 10\u0026ndash;60 degrees\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eShape\u003c/strong\u003e: Irregular\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eRoughness\u003c/strong\u003e: Rough\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eCoating\u003c/strong\u003e: Kaolinite / Calcite\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSpacing\u003c/strong\u003e: very wide, i.e. more than 2 meters\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003e3.5\u003c/strong\u003e\u0026nbsp;\u003cstrong\u003eBorehole number 149 (\u003c/strong\u003eTotal depth 50.30meter)\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec21\" class=\"Section2\"\u003e\n\u003cp\u003e\u003cstrong\u003e3.5.1\u0026nbsp;first layer\u003c/strong\u003e (Silt) is described as:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eColor\u003c/strong\u003e: Dark grey\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eMoisture\u003c/strong\u003e: Wet\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHardness\u003c/strong\u003e: Soft\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003ePlasticity\u003c/strong\u003e: Low plasticity\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cstrong\u003e3.5.2 Second layer\u003c/strong\u003e (Sand) founds in 2.70meter to 45.30meter and describes as:\u003cbr /\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eColor\u003c/strong\u003e: dark grey to grey\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGrain\u003c/strong\u003e: Fine to Coarse grain with some silt\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eShape\u003c/strong\u003e: Sub-rounded to angular\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGraded\u003c/strong\u003e: Poorly graded\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHomogeneity\u003c/strong\u003e: Homogenous rock\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eComposition\u003c/strong\u003e: Quartz \u0026amp; Feldspar\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGrain shape\u003c/strong\u003e: subrounded to subangular\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003e3.5.3 Basement\u003c/strong\u003e (Agglomerate rock ) at 45.30meter to 50.30meter describe as:\u003c/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eColor\u003c/strong\u003e: Reddish brown.\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGrain\u003c/strong\u003e: Coarse-grained\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHardness\u003c/strong\u003e: Massive\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSupport\u003c/strong\u003e: Grain supported\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eTexture\u003c/strong\u003e: Heterolithc texture\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSorting\u003c/strong\u003e: Poorly sorted\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eGranular\u003c/strong\u003e: Welded angular to sub- angular fragment, mainly rhyolite and part of ignimbrite.\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec22\" class=\"Section2\"\u003e\n\u003ch2\u003e3.5.4 Engineering Properties of Agglomerate\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eWeathering\u003c/strong\u003e: Slightly weathering along the joint plane\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eStrength\u003c/strong\u003e: Highly strength\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eRQD\u003c/strong\u003e: 46%- 100%\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eFresh water return\u003c/strong\u003e: 95% \u0026minus;\u0026thinsp;99%\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003cdiv id=\"Sec23\" class=\"Section3\"\u003e\n\u003ch2\u003e3.5.5 Joint Characteristics\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eAngle of dip\u003c/strong\u003e: 0.0\u0026ndash;10 degrees\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eShape\u003c/strong\u003e: Irregular\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eRoughness\u003c/strong\u003e: Rough\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eCoating\u003c/strong\u003e: Kaolinite / Calcite and Iron oxide\u003c/p\u003e\n\u003c/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eSpacing\u003c/strong\u003e: very wide, i.e. more than 2 meters\u003c/p\u003e\n\u003c/li\u003e\n\u003c/ul\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec24\" class=\"Section2\"\u003e\n\u003ch2\u003e3.6 Summery of Drilling Results\u003c/h2\u003e\n\u003cp\u003eThe drill borehole at the study area can identification of geological characteristics and engineering properties of the ground by knowing the structures and stability with types of joint characteristics that are summarized in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e showing the orientation, material filling, degree or spacing and all of this information can help to identification the characteristic of the basements and which stable area for a building project, subsurface layers various into sand and silt formation with basement rock type is Agglomerate.\u003c/p\u003e\n\u003cp\u003eThe selection of three boreholes is based on the location of the dam, and it surveyed the area of the project with given complete information at. That we observation the ground of the three boreholes is typically matched but there are some different in the thickness of a layer such as Agglomerate in the borehole number 412 is more than other, and it found at shallow while in the other borehole is found deep in the bottom it with thickness 5meter and in 412 is 50% of total depth is Agglomerate and sediment formation in top Sand, and Silt formation at drilling we test the strength of rock during drilling and used SPT test with permeability and joint characteristic to measurement the engineering properties of rock and that gives good evidence of the study area with complete data concerned to project, the drilling borehole by rotary rig with geotechnical engineering method and test.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab2\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eCorrelations between boreholes No. 403, 412 \u0026amp;149\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\u003ccolgroup\u003e\u003c/colgroup\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLocation\u003c/p\u003e\n\u003cp\u003eDescription\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLeft of Spill way channel\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eMisikitab island\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eRight of Spillway Channel\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\u003eBorehole number\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e403\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e412\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e149\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eTotal depth\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e61.10meter\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e35.00meter\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e50.30meter\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eRock types\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003esand / silt\u003c/p\u003e\n\u003cp\u003eagglomerate\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003esand / silt\u003c/p\u003e\n\u003cp\u003eagglomerate\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003esand / silt\u003c/p\u003e\n\u003cp\u003eagglomerate\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eAgglomerate depth\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e56.10 meter\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e17.85 meter\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e45.50 meters\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eRock Quality Designation (RQD)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e15% \u0026minus;\u0026thinsp;89%\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e80% \u0026minus;\u0026thinsp;100%\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e46% \u0026minus;\u0026thinsp;100%\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eBasement Weathering\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003efresh to slightly\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003efresh to slightly\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003efresh to slightly\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd colspan=\"4\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eJoint Characteristics\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\u003eAngle of dip\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e10\u0026deg; \u0026minus;\u0026thinsp;60\u0026deg;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0\u0026deg; \u0026minus;\u0026thinsp;45\u0026deg;\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0.0\u0026deg; \u0026minus;\u0026thinsp;10\u0026deg;\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eShape\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eIrregular\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eIrregular\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eirregular\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eRoughness\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eRough\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eRough\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003erough\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eCoating\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ekaolinite /calcite/iron oxide\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ecalcite/iron oxide\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ecalcite/iron oxide\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eSpacing\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003every wide\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eClose\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003every wide\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eFresh water return\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e99%\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e0%-20%\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e95% \u0026minus;\u0026thinsp;99%\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\u003eThe selection of three boreholes is based on the location of the dam, and it surveyed the area of the project with given complete information at. That we observation the ground of the three boreholes is typically matched but there are some different in the thickness of a layer such as Agglomerate in the borehole number 412 is more than other, and it found at shallow while in the other borehole is found deep in the bottom it with thickness 5meter and in 412 is 50% of total depth is Agglomerate and sediment formation in top Sand, and Silt formation at drilling we test the strength of rock during drilling and used SPT test with permeability and joint characteristic to measurement the engineering properties of rock and that gives good evidence of the study area with complete data concerned to project, the drilling borehole by rotary rig with geotechnical engineering method and test.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"CONCLUSION AND RECOMMENDATIONS","content":"\u003cp\u003eThe study was conducted to examine the suitability of the selected site for the proposed hydro-power dam that located on the River Nile at about 80 km north of Khartoum town. The site is located at the narrow gorge of the River Nile on the volcanic plateau that mainly occupied by acid volcanic rocks characterized by highly jointed rocks. The main fractures trends are in NW and NE that need to be considered during the dam implementation. The dam axis is located on the relatively less fractured Agglomeratic rocks, three borehole is typically matched but there are some different into the Depth of Basement (Agglomerate)\u003c/p\u003e\u003cp\u003eThis study has recommended that This research work suggested that during construction phase the engineering geologist should take worry of horizontal lithological variation by taking\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlmond DC, Ahmed F (1993) Field guide to the geology of the Sabaloka Inlier, Central Sudan. Khartoum University Press, Khartoum Sudan\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlmond DC (1980) : \u003cem\u003ePrecambrian events at Sabaloka, near Khartoum, and their significance in the chronology of the basement complex of North-East Africa, Precambrian Research, Volume 13, Issue 1, September 1980,Pages 43\u0026ndash;47, 51\u0026ndash;62\u003c/em\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBieniawski ZT (1973), : \u003cem\u003eEngineering Classification of Jointed Rock Masses, Paper in THE CIVIL ENGINEER in South Africa - December 1973 pages 335\u0026ndash;343\u003c/em\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDawoud AS, Dobric B (eds) (1993) : \u003cem\u003ePT Condition of Pan African Granulite Facies Metamorphism in Sabaloka Inlier North of Khartoum, Sudan. Geo Sci.Res. In North East (ed) Thoreweihe and Schandelemeier. (Stern, 1994)\u003c/em\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDawoud AS, Sadig AA (1988) Structural and Gravity Evidence of an Uplifted Pan African Terrain in Sabaloka Inlier. J Afr Earth Sci 7:787\u0026ndash;794\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDelany FM (1958) Observations on the Sabaloka Series of Sudan, Transactions of the geology Society of South Africa. 61:111\u0026ndash;124\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eElyas M (2016) : The Geology and Structure of the Precambrian Basement Rocksof the Sabaloka Inlier, North Khartoum, Sudan: Remote Sensing and Petrological Approaches. M. Sc. Thesis, Al Neelain University\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKroner A, Stern RJ, Dawoud AS, Compston W, Reischmann T (1987) The Pan- African continental margin in northeastern Africa: evidence from the geochronological study of granulite at Sabaloka, Sudan. Earth Planet Sci Lett 85:91\u0026ndash;104\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePalmstr\u0026ouml;m (1995) : \u003cem\u003eDesign and Construction of underground Structures, New Delhi, Norwegian Geotechnical Institute 23\u0026ndash;25 February 1995\u003c/em\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVail JR (1985) : \u003cem\u003eAlkaline ring complexes in Sudan. Dept. Geol. Portsmouth Polytechnic, U.K. Vol.13, 51\u0026ndash;59.\u003c/em\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Sudan University of Science and Technology","isAcceptedByJournal":false,"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":"boreholes, geotechnical analyzes, River Nile, Sabaloka dam, Sudan","lastPublishedDoi":"10.21203/rs.3.rs-6092009/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6092009/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe Sabaloka dam is located at the Sabaloka igneous complex on the sixth cataract of the Nile, proposed for multi-purposes, mainly for hydro-power generation and irrigation in addition to help in minimizing the siltation for the Merwe dam to the north. Moreover, it will represent an excellent habitant for fisheries in the lake behind the dam.\u003c/p\u003e\n\u003cp\u003eThe study relied on field tests, well data, and analysis, in addition to the structural analysis of fractures in the examined site.\u003c/p\u003e\n\u003cp\u003eObserving the results of drilling, the three boreholes are usually identical in lithology, where silt sands and conglomerates appear, but there is some difference in the depth of aggregation, in addition to the difference in the designation of rock quality (RQD), which decreases in borehole 403 in the left channel, due to the existence of Two sets of joints across the dextral fault.\u003c/p\u003e\n\u003cp\u003eThe proposed dam axis is located in the relatively less fractured Agglomeratic rocks. The main fracture trends are NW and NE directions and cut, respectively, the western and eastern flanks of the dam axis.\u003c/p\u003e","manuscriptTitle":"Engineering Geological Characterization of Proposed Sabaloka Dam Site","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-02-26 07:42:48","doi":"10.21203/rs.3.rs-6092009/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":"a6ed09a1-5245-4a44-b8a6-2ab5fe5635f4","owner":[],"postedDate":"February 26th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":44885410,"name":"Geology"}],"tags":[],"updatedAt":"2025-02-26T07:42:48+00:00","versionOfRecord":[],"versionCreatedAt":"2025-02-26 07:42:48","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6092009","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6092009","identity":"rs-6092009","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}