Different Types and Formation Mechanisms of Karst Collapse in Huainan City

Different Types and Formation Mechanisms of Karst Collapse in Huainan City | 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 Different Types and Formation Mechanisms of Karst Collapse in Huainan City Miao Liang, Guangquan Xu, Tingting Yang, Haitao Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6918019/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Apr, 2026 Read the published version in Carbonates and Evaporites → Version 1 posted 7 You are reading this latest preprint version Abstract Karst collapses have been occured ,which brings potential geological hazard for the risk of construction of mining cities and the ecological environment restoration. By the methods of field geological survey, statistical analysis and numerical simulation methods, the characteristics and distribution of karst collapses have been investigated systematically along such areas as Shungeng Mountain, Liyingzi,Tubazi,and Fengtai County, and the formation conditions and types of karst collapse are discussed, and the formation mechanisms are simulated under different conditions.The results show that influenced by the combined actions of stratigraphy, lithology, geological structure and hydrogeological conditions, karst collapses mainly develop in the Ordovician and Cambrian strata covered with the unconsolidated sediments, which is distributed concentrately along the strikes of strata and near fault tectonic zones. Based on hydrogeological conditions, dip of strata, and induced factors, karst collapses can be classified into four types:steeply dipping, gently dipping, overturned under dewatering conditions, and the variable load of overlying soil. In order to understand the formation mechanism of karst collapses, FLAC 3D software is used to simulate and analyze the variation about displacement and effective stress at different designed observed points ,along vertical cross section covered with unconsolidated sediments during the processes of dewatering in coal mines and urban construction. The study of formation process of karst collapse provides important guidance for the prevention and control of karst collapse disasters. Carbonate rock of Cambrian and Ordovician karst collapse induced factors formation mechanism Huainan city Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Introduction Karst collapse is the phenomenon in which the covered carbonate rocks undergo chemical dissolution, physical deformation, and mechanical collapse under the influence of physical, chemical, and gravitational processes, resulting in surface deformation and collapse disasters（Zhang et al.2005;Yan 2022;Liu et al.2020）. Due to the differences in lithology, structure and attitude of strata, hydrogeological conditions, and induced factors, the location and timing of karst collapses occur with a certain degree of randomness, suddenness, and unpredictability, which brings both opportunities and challenges for the prevention of karst hazards and also has being attracted widespread attention at home and abroad (Xu 2024;Si 2023). Over the years, relatived surveys and research are about the formation conditions of karst collapse, including strata, structure, meteorology, and hydrodynamics, as well as human activities. Focusing on the distribution patterns and developmental characteristics of karst collapses, as well as their induced mechanisms, several theories have been successively proposed, including the theory of suffosion, chemical dissolution, pressure effect, vacuum suction theory, and hydraulic fracturing theory (Xu et al.1981;Wang et al.2017;Hu 2022;Wu etal.2021;Caupin et al.2006;Mcmanus et al.1997;Standing et al.2013;Thomas et al.1999;Standing et al.2013;Li et al.2024;Luo et al.2021;Chen et al.2014;Che et al.2021;Zhang et al.2022;Qin et al.2021). Furthermore, simulations and analyses have been carried out by the FLAC 3D and LBM-DEM software, combined with elastoplastic theory and variable saturation seepage theory, to restore the evolution process of karst collapse and reveal the mechanisms of collapse formation (Xiong et al.2022;Tao et al.2024;Li et al.2022;Yu et al.2020;Chen et al.2024;Xiong et al.2022). The study area is located in the southern part of the Huainan Coalfield, at the southern margin of the North China Block. Due to the influence of multi-period geological tectonic movements and long-term dissolution and erosion from surface water and groundwater.The development form of karst has diversity and complexity.(Xuan et al.1999;Li et al.2018;). Karst collapses have occurred due to the dewatering during mining activities. Karst geological surveys results show that internal factor is closely related to lithology, stratigraphic combination, geological structure, and hydrogeological conditions, and the main induced factors is involved to the variation of groundwater level during drainage and overlying loads (Li et al.2018;Huang et al.2012;Chen et al.1990; Yu et al. 2024; Jia et al. 2021). Above-mentioned studies have provided some reference for the prevention and control of karst collapse disasters in Huainan (Feng 2021;Zhang 2021). However, with the successive closure of coal mines along the Bagong Mountain-Shungeng Mountain area and the acceleration of urbanization, the hydrogeological conditions of karst have been changed. Therefore, it is necessary to study the distribution patterns and types of collapse furtherly, systematically analyzing influened factors and formation mechanisms which will provide a basis for the ecological restoration of closed mines and the prevention and control of karst collapse disasters during urban construction. 1. Background of geology Huainan ctiy is located near Huai River in Anhui province, which is characterized by subtropical and warm temperate hills and plains. In the exposed carbonate rocks, the water from atmospheric precipitation along the surface and infiltrates into the underground carbonate strata, recharging the shallow karst aquifer covered by loose layers. Weathering and erosion occur continuously when groundwater infiltrate through channels such as faults, fractures, and dissolution pores in the shallow carbonate aquifer(Filipović et al.2025). This is especially evident in the Ordovician and Cambrian karst aquifer systems covered by the sediment of Quaternary system, where strong flow zones are formed along the breccia zones of faults(Kaufmann et al. 2016). Therefore, there is a close hydraulic connection between the precipitation and shallow karst groundwater (Li et al.2024). The study area includes Shungeng Mountain and Bagong Mountain, where the Archean Huoqiu Group, Proterozoic Qingbaikou System and Sinian System, Paleozoic Cambrian, Ordovician, Carboniferous, and Permian strata, as well as Mesozoic Triassic strata are exposed from south to north, as shown in Fig. 1 . From the tectonic perspective, the study area is located on the southern margin of the North China Coalfield, bounded by the Fufeng Reverse Fault to the north, and the Fuli Normal Fault to the south, the Changfeng Fault to the east, extending to the Fengtai County town to the west. Under the action of thrust and compression structures, Shungen Mountain and Bagong Mountain are distributed along the near EW and NNW, respectively, which have been influenced by multi-period tectonic geological processes, including Caledonian uplift, Indosinian compression, and Yanshanian extension, leading to the development of faults of different ages. The main faults include the Fufeng reverse fault, the Shungen Mountain reverse fault, and the Fuli normal fault, which are the boundary faults of the thrust sheet. In addition, small faults trending in the SN and NNW have developed within the thrust sheet (Fig. 1 ). Shungeng Mountain is composed of two segments: Jiulonggang-Quanshan and Luoshan, influenced by the thrust tectonic activity, which strata have been overturned. From east to west, the dip angle of the strata decreases progressively from 85° to 20° along the strike. Only in the area of Jinjialing-Quanshan are the Carboniferous and Permian coal-bearing strata exposed as intercalations. The Luoshan segment is composed of the Archean Huoqiu Group, the Upper Proterozoic Qingbaikou System and Sinian System, and the Mesozoic Triassic strata, and also is a thrust nappe block. The Luoshan thrust block exerts a compressive thrust effect on the block on the east side of Bagong Mountain,inducing the Ordovician, Carboniferous, and Permian strata in the Liyingzi area to be overturned. In the Bagong Mountain segment, the strata trend is nearly along the NNW and dip to the northwest, which is divided into two geological blocks by the Shanwangji Fault: the Liyingzi-Xinzhuangzi block and the Shanwangji Fault-Fengtai block. The former consists of normal monoclinic strata with a dip angle of about 20°,and the latter's strata with a dip angle of about 80°. The main faults are distributed along the NNE and NW (Li et al.2018). The karst strata are covered by Quaternary loose sediments with a thickness of 0–15 m, where are prone to karst collapse (Figs. 1 and 2 ). The development of dissolved pores and fractures leads to some differences in the storage capacity and permeability, especially in fault zones where tectonic karst brecciations is well-developed, such as the Shanwangji Fault zone and the Shungeng Mountain Fault zone.And with the influence of dewatering from mining activities and domestic water use by residents, the groundwater level in the shallow karst areas has dropped significantly.This has resulted in the depression cones of groundwater, which has accelerated the dissolution and suffosion in the shallow carbonate rock strata inducing karst collapse (He et al. 2018;Zhou et al. 2016;Li et al.2015;Liu et al.2014; Sevil et al. 2017). 2 Characteristics of karst collapse Since 1952, a total of 131 karst collapses have been occured which appeared in clusters, mainly along the Bagong-Shungeng Mountain Fengtai County, Kongji, Tubazi, Liyingzi, Jiulonggang, and Datong.These karst collapses are situated in the carbonate rock strata of the Majiagou Formation in the Ordovician System. The investigated results are shown in Table 1 . The karst collapses with circular, elliptical, and elongated shapes ,develop along the trend of strata and fault structures, and also are filled with loose sandy soil under the influence of changes in the shallow groundwater level and urban construction(Guo et al.2024). Table 1 Statistics of karst collapse investigation in Huainan Names of karst collapse clusters Location Numbers Stratum Geometric shape Geometric dimensions/m depth/m Length/m Width/m Radius/m Fengtai County seat collapse cluster Fengtai County seat 4 Majiagou Formation Near-elliptical or circular / / 0.1 ~ 6.5 3 ~ 5.5 Kongji collapse cluster Kongji 6 Majiagou Formation Elongated shape / / 14 ~ 16 0.5 ~ 3.9 Tubazi collapse cluster Bagong Mountain soap factory 30 Majiagou Formation Circular, elliptical, and elongated shape 3 ~ 95 3 ~ 15 10 3 ~ 7.5 Daguadi Majiagou Formation Bead-like and circular 5 ~ 20 3 ~ 9 3 ~ 10 1 ~ 12 Liyingzi collapse cluster Chunshenjun Mausoleum 3 Majiagou Formation Circular, elliptical, and elongated shape 8 ~ 10 2 ~ 5 1.5 0.2 ~ 1.6 Shungeng Mountain collapse cluster Qishanji Pear Orchard 66 Zhangxia Formation Irregular elliptical shape 0 ~ 60 0 ~ 40 / 0.1 ~ 6 Datong Cement factory Majiagou Formation Circular or other shapes 0 ~ 20 0 ~ 10 1.5 0.2 ~ 10 Wuceng ~ Dongshan mountain 4 Zhangxia Formation Circular 0.2–0.5 0 Shengjiagang 9 Majiagou Formation Circular / / 1.5 ~ 13 1 ~ 2 3 Discussion 3.1 Influencing factors of karst collapse The formation of karst collapse is not only related to strata structure, lithology, and geological structure, but also to the thickness of covered clay and sand layers and the groundwater hydrodynamic conditions (Liu et al.2014;). Survey results have revealed that the Zhangxia Formation of the Cambrian System mainly consists of dolomitic oolitic limestone and bioclastic limestone, while the Majiagou Formation of the Ordovician System is predominantly composed of calcareous dolomite and dolomite. According to the drilling data, the karstification rate of the Majiagou Formation ranges from 10.3–17.16%, and that of the Zhangxia Formation of the Cambrian System ranges from 9.3–13.3% (Huang et al.2012;He et al.2018;Han et al.2021). Among 131 karst collapses ,16.0% occur in the Zhangxia Formation, and 74.81% occur in Majiagou Formation, mainly distributed in the limestone and dolomitic limestone strata. Due to the influence of overturning tectonic movements, the strata had been tilted and overturned, with the development of normal and reverse faults of different types and scales, with high-angle tension fractures and fault breccia zones which provide pathways for groundwater flow, and which also is one of the important controlling conditions for the formation of karst collapses (Liu et al.2014;Ding et al.2020;Jin et al.2018;Xu et al.2004). Especially, in Shungengshan reverse fault, and Shanwangji normal fault zone, and other smaller fault systems, dense fracture networks often form. These networks enhance the dissolution and piping effects of groundwater on carbonate strata, also accelerating the formation process of karst collapses. 3.2 Induced types of karst collapse The karst in the southern part of the Huainan coalfield belongs to the typical northern karst. There are many commonalities in the formation conditions of karst collapse from the outcrop area to the covered area, but there are still some differences in the induced mechanisms. Based on the formation conditions and induced factors, the karst collapses are divided into the following four types. (1)The type of karst collapse induced by dewatering during mining The strata are affected by the thrust structure. The attitude of strata outcrops changes in different geological blocks and can be divided into steeply dipping, gently dipping, and overturned. The statum dip angles not only alters the groundwater flow patterns, but also plays a significant controlling role in the development of karst. The groundwater flow patterns from horizontal to vertical direction have caused the change in the karst development morphology from horizontal layer shapes to vertical cylindrical shapes. Consequently, the plane shape of karst collapses has also been shifted from elliptical to circular. During the concentrated dewatering of the Carboniferous limestone aquifer during coal mining, the run off zones of groundwater were formed along the fault zone around the mines, which caused a static imbalance between the collapsing soil and rock mass and the groundwater, thereby inducing karst collapses. According to the different strata dip angles, three types can be distinguished as follows: (1)The type of karst collapse in steeply dipping strata The karst collapses in steeply dipping strata is mainly distributed in the Datong and Kongji ,which is influenced by the Shungengshan thrust nappe structure and the Shanwangji tension fault zone. Due to the large dip angles of strata, the development of karst is concentrated in the intersections of structural fractures and solution fissures that are perpendicular or oblique to the strata trend, and during the dewatering and pressure reduction by action of dewatering, the pore water pressure of the soil and rock is reduced. The loose sand and soil filling in the caves are disturbed, and the destruction of original stress balance leads to the formation of karst collapse.(Fig. 3 a、b) (2)The type of karst collapse in gently dipping strata The karst collapse in gently dipping strata mainly occurs in the Tubazi area. Influenced by tectonic activity, vertical or oblique fractures develop along the bedding planes of strata and are filled with Quaternary loose materials. During the dewatering, the groundwater exerts the disturbed effect on the loose soil,and soil caves continue to expand. The effective stress carried by the soil particle and the pore water pressure gradually decrease. Under the action of the overlying strata load, karst collapse is formed.(Fig. 3 c、d).This type of collapse appears as a string of beads in plan view, and the collapse area is relatively large. (3)The type of karst collapse in overturned strata These karst collapse are mainly distributed in the Liyingzi area. Influenced by the Shungengshan thrust nappe, the strata are overturned at the fault bend and develop multiple vertical or oblique tension fractures along the bedding planes.These fractures are filled with loose Quaternary sediment at their intersections.Due to infiltration from atmospheric precipitation and groundwater flow, a unified karst groundwater flow field is formed in the Ordovician and Carboniferous systems.Later, dewatering and pressure reduction during mining activities cause the loose soil and water mass to become unbalanced, leading to collapse.(Fig. 3 e、f).This type of collapse appears as elongated shapes in plan view, with narrow width ranges. (2) The type of karst collapse induced by changes in gravity load These karst collapses induced by changes of gravity load due to urban construction mainly occur in the Political New District of Fengtai County. The Quaternary loose strata overlie the karst strata of Cambrian and Ordovician, and influenced by the Shiwangji normal fault and long-term weathering and erosion. The degree of cave development is relatively higher. In recent years, with the intensification of urban construction, the increased overlying load has altered the pore water pressure and effective stress of the soil and water in the caves,which is loss of balance in the rock-soil-water system, ultimately resulting in karst collapse(Lyu et al. 2024; Zhang et al. 2022). 3.3 The formation mechanism of karst collapse In order to further reveal the formation mechanism of karst collapse in shallowly covered carbonate area, and predict karst collapse disaster caused by the above two induced factors, FLAC 3D was used to simulate two scenarios respectively: one is the decline of karst groundwater level caused by dewatering and pressure reduction during mining ; the other is the disturbance of the stress balance states due to the increase in overlying load by urban construction, which causes instability and subsequent ground karst collapse. 3.3.1 Design of Karst collapse model (1)Geological model of karst collapse Based on previous drilled geological data and field karst geological surveys, the lithostratigraphic structure mainly consists of two layers in the karst collapse area. The first is a loose sandy and soil layer, with the upper segment being clay and the lower segment a confined sandy aquifer. The second is a carbonate karst strata, developing caves at different depths that are filled with overlying loose sandy soil and form close hydraulic connections with groundwater. According to the relationship between the loose aquifer and karst collapse, a model of the overlying loose aquifer and underlying karst collapse aquifer was established(Wang et al,2022). The model dimension is 80m × 80m × 120m, where the thickness of the overlying sandy soil layer is 10m and 20m, respectively, and the thickness of the underlying carbonate rock layer is 30m and 60m, respectively. The cave within the model is 10m wide and 30m high, as shown in Fig. 4. (2)Boundary conditions of the model In order to analyze the deformation and failure process of the potential collapse soil layer caused by internal stress changes induced by gravity and groundwater level fluctuations, the influence of horizontal tectonic stress can be neglected. A vertical loading method (0 kN to 0.9 kN) is adopted, and the variation in the groundwater level is within the range of 5 m to 30 m. Unidirectional constraints are applied to the lateral boundaries and the ground surface boundary of the model, while the model surface is set as a free boundary. (3)Parameters The elastoplastic models built should match the Mohr-Coulomb criterion and Darcy's law. During the simulation process, the deformation parameters of the rock and soil mass are represented by the shear modulus (G) and the bulk modulus (K). The deformation modulus is converted into the shear modulus and bulk modulus using Equations (1) and (2): In the above equations, µ is the Poisson's ratio of the overlying rock and soil mass, and E 0 is its deformation modulus. (4)Simulation scenarios Based on the soil layer, stratum structure as well as the hydrogeological conditions of karst, one simulation scenario is to model karst collapse induced by dewatering and depressurization during mining, with simulations carried out for the decline of groundwater level. The second, without considering changes of the water level, and only taking into account the increase of the overlying load due to urban construction, and the simulation is conducted according to the application of different loads. (5) Model establishment and discretization Through the analysis of the above-mentioned models and scenarios, the strata parameters are determined based on geological drilled data(Xu et al.2004). A numerical model of karst collapse, such as multi-layer, has been established. The model structure consists of five parts(Table 2 ). The model is designed with 157,378 grid points and a total of 255,056 grid units. Table 2 Mechanical parameters of different layers Region Density (kN/m 3 ) Tensile strength (kPa) Angle of internal friction (°) Cohesion(kPa) Bulk Modulus (MPa) Shear Modulus (MPa) clay layer1 2400 4.0 21 70 13.5 57.6 sandy soil layer2 2300 1.0 32 30 9.8 73.8 Karst area 2300 1.0 32 30 9.8 73.8 Rock layer1 2600 3000 36 170 18 112 Rock layer2 2900 5000 38 130 19 136 3.3.2 The mechanism of karst collapse induced by dewatering Using the above-mentioned model, the process of dewatering karst groundwater under coal mine mining conditions was simulated. The overall changes in surface displacement, as well as the variations in effective stress and displacement over time at corresponding points in the karst strata, were analyzed when the groundwater level dropped to 5 m, 10 m, 15 m, 20 m, and 25 m, as shown in Figs. 5 , 6 , and 7. The simulation results indicate that affected by the dewatering during mining and the domestic water use of urban residents, the groundwater levels in different aquifers continuously decline which leads to a reduction in the pore - water pressure within the rock and soil mass, causing changes in the stress of the caves. As a result, the stability of the sandy soil filling the karst caves is disturbed,and the original stress balance is broken, and ultimately, the karst collapses have occurred. 3.3.3 The mechanism of karst collapse induced by overlying loads To reveal the stress and strain conditions at different depths under various loading conditions within the potential karst collapse area, six probe points were set up along the vertical direction to obtain the deformation and force conditions at corresponding locations, as shown in Fig. 4(c). The simulation results show that the accumulated deformation near the top of the cave is relatively significant, and the settlement is positively correlated with the fixed load, showing a downward trend. As the fixed load increases from 0 kPa to 9 kPa, the surface settlement increases from 29.98 mm to 578.08 mm. The displacement of the two soil layers above the cave changes significantly with the fixed load, while the underlying rock layer is relatively stable with a small deformation. As the load increases, the nephograms of surface displacement and the curves of displacement and effective stress of corresponding points over time are shown in Figs. 8 , 9 , and 10. The above simulation indicates that the occurrence of karst collapse in urban construction is mainly due to the increased overlying load,which leads to the changes in the hydrostatic pressure stress of the soil-water body filling the karst caves and the effective stress of the rock and soil mass.This results in the imbalance of the rock-soil-water body filling the karst caves, and subsequently causing the collapse of the karst cave strata of the Cambrian and Ordovician systems covered by the Quaternary system. 4 Conclusion Through the investigation of karst collapses in Huainan city, the formation conditions, karst strata and patterns have been analyzed, and the formation process of karst collapses was revealed with a mechanistic perspective. The main conclusions are as follows: Influenced by thrust nappe tectonic movement, lithology of strata, atmospheric precipitation, and the thickness of loose cover, karst collapses are mainly distributed along the bedding direction, fault zones, shallow loose covered area, and urban construction zones. From the outcrop to the shallow burial area, karst collapses occur in the strata of the Cambrian Zhangxia Formation and the Ordovician Majiagou Formation, and the plane shapes of the collapses are mostly circular, elliptical, and strip. Karst collapses are formed along fault fracture zones of soluble rock strata, and carbonate strata covered by loose layers. According to the genesis and induced factors, the karst collapses can be divided into four patterns, namely ,steeply dipping, gently dipping, and overturned patterns, as well as karst collapse patterns related to gravitational load. During the process of groundwater level decline during dewatering and with increase of overlying load from urban construction, there are significant differences in the displacement and effective stress changes within the karst-soil-groundwater- internal structure. Therefore, the manifestation of karst collapse processes varies under different hydrogeological conditions and induced factors. The areas around Fengtai County city, Bagong Mountain and Shungeng Mountain will still be the regions where karst collapses are likely to occur in the future. It is necessary to further monitor and prevent possible karst collapses to occur,focus on concealed areas of the groundwater recovery zones after the mines are closed and the urban construction areas, and carry out active and effective prevention measures. Declarations Author Contribution ML wrote the main manuscript text, GX revised the manuscript text, TY prepared figures and tables, and HZ provided important materials. All authors reviewed the manuscript. Acknowledgments This paper is supported by the National Natural Science Foundation of China (No. 42172279) .The great supports from the Huaihe Energy Holding Group Co., Ltd. of China, and the State Key Laboratory of Anhui University of Science and Technology are greatly appreciated. References Zhang JG,2005.Karst process and its lmpact on construction stability of the slope terrain within muddy limestone in the Three Gorges region.J.Acta Geoscientica Sinica (06):565-569. Yan LBQ,2022.Characterization of Occurrences of karst collapses in Guilin and assessment of their future trend.D.Guilin University of Technology. Liu CZ,Chen CL ,2020. Achievements and countermeasures in risk reduction of geological disasters in China.J. Journal of Engineering Geology 28( 2) : 375-383. Xu SL,2024.Analysis of the formation mechanism and prevention and control measures of karst collapse geological disasters in Suixi County, Huaibei City.J.Ground water 46(03):201-203. Si ZY,2023.Brief Analysis of the Mutual Influence Relationship between Hydrogeological Conditions and Geological Disasters of Karst Collapse: A Case Study of the Panjia Laowu Area in Yueshan Town, Huaining County.J.Western Resources (02):103-105. Bouzerda M, Mehdi K, Boualla O, Fadili A, Najib S, Saied M,2024 . Inventory and geomorphological analysis of karstic collapse dolines in Sahel-Doukkala (Morocco). Carbonates Evaporites 39, 93. Xu WG,Zhao GR,1981.The implication of suction action for ground subsidence in karst mining areds.J.Geological Review (02):174-180+183. Wang F,Chai B,Xu GL,Chen L,Xiong ZT,2017.Evolution mechanism of karst sinkholes in Wuhan city.J.Journal of Engineering Geology 25(03):824-832. Hu CL,2022.Formation of karst collapse induced by combined action of water and gas mechanism research.D.Chongqing Jiaotong University. Wu YB, Yin RC, Lei MT, Dai JL, Jia L, Pan ZY, Ma X, Zhou FB,2021.Triggering factors and prevention-control countermeasures of karst collapses caused by tunnel construction in the Zhongliangshan area, Chongqing.J.Carsologica Sinica 40(02):246-252. Caupin F, Herbert E,2006. Cavitation in water: a review.J. Comptes rendus - Physique 7(9-10):1000-1017. Mcmanus K J, Davis R O, 1997. Dilation-induced pore fluid cavitation in sands.J. Géotechnique 47(1):13-177. Standing J, Ghail R, Coyne D,2013. Gas generation and accumulation by aquifer drawdown and recharge in the London Basin.J. Quarterly Journal of Engineering Geology and Hydrogeology 46(3):293-302. Thomas M Tharp,1999. Mechanics of upward propagation of cover-collapse sinkholes.J].. Engineering Geology 52:23-33. Standing J, Ghail R, Coyne D,2013. Gas generation and accumulation by aquifer drawdown and recharge in the London Basin.J. Quarterly Journal of Engineering Geology and Hydrogeology 46(3):293-302. Li JT,Zhu K,Xiao XX,Yin Y,Liu H,Xu M,He ZP,2024.Development mechanism of covered karst collapses induced by groundwater drawdown.J.Carsologica Sinica 43(2):406-420. Luo XJ,Luo C,2021.Three-Mechanism Theory (TMT) of karst ground collapse and its application.J.Carsologica Sinica 40(02):171-188. Chen LJ,Sun XL,Pi J,Wang C,Ou J,2014.Distribution characteristics and factors influencing karst collapse in Dachengqiao,Ningxiang,Hunan.J.Carsologica Sinica 33(04):490-497.. Che ZG,Liu H,Yu YX,2021.Study on geological conditions and formation mechanism of karst collapse in JiangdongVillage,Jinting Town,Suzhou City.J.East China Geology 42(01):85-92. Zhang ZS,2022.Origin and trend analysis of karst collapse in Huangqi and Haibei communities, Foshan City.J.Carsologica Sinica 41(6):880-894. Qin JW,Song GX,Pan GM,2021.Cause and law of karst collapse in the urban complex environment:An example of Beihuanxincun, Guigang City.J.Carsologica Sinica 40(02):230-237. Xiong QH,Gao X,Xu Q,Wang RQ,Li ZC,Tao L,2022.Dynamic evolution numerical model of cover-collapse sinkholes.J.Safety and Environmental Engineering 29(01):85-92. Tao XH,Ye M,Gong JS,Wang HS,Hu XY,2024.Analysis of the formation process of the covered karst ground collapse induced by groundwater changes based on the coupled LBM-DEM numerical simulation at micro scale.J. The Chinese Journal of Geological Hazard and Control 35(1): 124-131. Li ZY,Lin LP,Li BH,2024.Numerical simulation of karst collapse in limestone mining areas based on FLAC3D.J.Scientific and Technological Innovation (22):33-36. Yu LH,Yan JL,Yu XJ,Hu ST,2020.Evolution and numerical simulation of karst caves based on FLAC3D.J.Ground water 42(04):55-57. Chen XJ,Xue MM,Song Y,2024.Influence of water level dropping rates on the collapse of karst soil caves.J.Carsologica Sinica 43(04):922-936. Xiong QH,Gao X,Tu J,Wang RQ,Yan EC,Li ZC,2022.Mechanism of soil - cave type karst collapse under negative pressure and its mechanical model.J.Yangtze River 53(09):163-168+180. Xuan J,Yang SL,1999.The basic features of kast collapse and preliminary study on their forming mechanism in the tubazhi district of huainan city.J.Geology of Anhui 9(4):301-306. Li ZH,Xu GQ,Gao JL,Zhang HT,Yang TT,2018.Characteristics of karst development and collapse mechanism in Shungeng Mountain,Huainan,Anhui Province.J.The Chinese Journal of Geological Hazard and Control 29(2):86-93. Li ZH,Xu GQ,Gao JL,Zhang HT,Yu ST,2018.Characteristics of structure and their influence on karstification in Huainan area.J.Coal Geology & Exploration 46(3):121-126. Huang H,Yan JP,Piao CD,2012.Karst collapse distribution and land-use feasibility of shallow overburden type karst area in Datong District,Huainan City.J.Journal of Natural Disasters 21(2):112-117. Chen ZY,1990.Discussion about karstic surface collapses in Huainan mining area.J.Journal of Huainan mining institute 10(2):1-7. Yu XG,Wang SC,Su BC,Zhang WQ,2024.Exploration and prediction of high pressure dynamic water hidden collapse column in coal mines.J.Water Resources and Industry,31,100250. Jia, L., Meng, Y., Li, L. et al. A multidisciplinary approach in cover-collapse sinkhole analyses in the mantle karst from Guangzhou City (SE China).J.Nat Hazards 108, 1389–1410 (2021). Feng YW,2021.Distribution and genesis of karst collapse in Shandong Province.J.Carsologica Sinica 40(2):205-214. Zhang HT,2021.Formation Mechanism and Prediction of Ordovician Paleokarst in Huainan Coalfield.Huainan:Anhui University of science and technology. Ivona Ivkić Filipović, Nikolina Ilijanić, Slobodan Miko, Ozren Hasan, Dea Brunović, Branko Kordić, Uroš Barudžija, Željka Sladović,2025.Late Quaternary geomorphology and sedimentary processes in the Prološko Blato karst wetland (Imotsko Polje, Croatia).J.Geomorphology.482,109765. Kaufmann G,Romanov D,2016.Structure and evolution of collapse sinkholes: Combined interpretation from physico-chemical modelling and geophysical field work.J. Journal of Hydrology,540:688-698. He B,Gao P,2018.Development characteristics analysis and prevention countermeasures of karst ground collapse in Jiulonggang area of Huainan City.J. Resources Information and Engineering 33(01):173-175. Zhou XP.Zhang CL,Ma JG,Liu MC,Ma L,Qian JZ,2016.Characteristics of multiple aquifers groundwater system in hugely thick Cenozoic stratum in Huainan.J.Journal of hefei university of technology(Natural Science) 39(12):1693-1697. Li X,Xu GQ,Wang MH,Liu MC,Ma JG,2015.Groundwater and its influencing factors in panxie coal mine area.J.Coal Technology 34(01):182-184. Xu GQ,Sun FY,Liu LH,Li PQ,Wang MH,Liu MC,2016.Evolution process and prediction of karstic geologic abnormal bodies in Panxie coal mining area in Huainan.J.Coal Geology & Exploration 44(1):62-68. Liu MC,Xu GQ,Liu LH,Li ZF,Dou CY,Jin XR,2014.Application of tracing test in detection of water inrushing channels in limestone aquifer.J.Coal Geology & Exploration 42(5):50-54. Sevil J, Gutiérrez F, Zarroca M, Desir G, Carbonel D, Guerrero J, Linares R, Roqué C, Fabregat I,2017.Sinkhole investigation in an urban area by trenching in combination with GPR, ERT and high-precision leveling. Mantled evaporite karst of Zaragoza city, NE Spain.J.Engineering Geology,231:9-20. Guo SL, Yan CH, Yu LC, Liu Y, Yan C,2024.Characteristics of shallow buried karst and its safety distance to tunnel in wuxi city, China.J.Quaternary Science Advances,13,100139. Han QD,Luo XY,2021.Analysis on the formation mechanism and development process of karst collapses in Lijia Village, Gaoming District of Foshan City.J.The Chinese Journal of Geological Hazard and Control 32(4):56-64. Jin QZ,Ruan XY,Liu Lu,2021.Ground collapse in the Tubazi area of Huainan City and the ountermeasures.J.Geology of Anhui Ding TF,Wang MH,Zhao JF,2020.Genesis analysis and study on tectonic control on water of Huainan North China-type coal field.J.Coal Geology & Exploration 48(4):102-108. Jin QZ,Xu D,Liu L,2018.Geological disaster exploration report of Tubazi karst ground collapse in Bagongshan, Huainan City.R. Anhui Geological Environment Monitoring Station. Lyu XR, Ju BS , Wang B , Wu XW , Ding YZ,2024.Mechanism, mode, and prediction of karst caves collapse in the deep marine carbonate fracture-cavity reservoir.J.Marine and Petroleum Geology, 167,106978. Zhang K, Zheng WB, Liao ZY, Xie HP, Zhou CT, Chen SG,Zhu JB,2022.Risk assessment of ground collapse along tunnels in karst terrain by using an improved extension evaluation method.J.Tunnelling and Underground Space Technology,129,104669. Wang XM, Wang SM, Peng XY, Ma TY, Chen B,2022.Equivalent numerical simulation method and application in karst-induced collapse of overlying sandy stratum.J.Engineering Failure Analysis,137,106280. Xu GQ,Shen HZ.Analysis on the land collapse induced by pumping groundwater —Huainan Coal Mine as an example.J.The Chinese Journal of Geological Hazard and Control 2004,15(4):67-71. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 02 Apr, 2026 Read the published version in Carbonates and Evaporites → Version 1 posted Reviewers agreed at journal 16 Aug, 2025 Reviewers agreed at journal 13 Aug, 2025 Reviewers agreed at journal 11 Aug, 2025 Reviewers invited by journal 10 Aug, 2025 Editor assigned by journal 23 Jun, 2025 Submission checks completed at journal 18 Jun, 2025 First submitted to journal 17 Jun, 2025 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-6918019","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":501221794,"identity":"47574652-4e1b-4f56-8de4-20f357e38615","order_by":0,"name":"Miao Liang","email":"","orcid":"","institution":"Anhui University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Miao","middleName":"","lastName":"Liang","suffix":""},{"id":501221795,"identity":"84f6665a-6161-4263-8e75-2dfc6fc8bcb4","order_by":1,"name":"Guangquan Xu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAs0lEQVRIiWNgGAWjYLCCj/9sePj5G0jQwTiDLU1GcsYBErQwc7AdtjFoSCBSubx7jpk0A895HgOGA4wfPuYQocXwzLM06QKJ2zzmzA3MkjO3EaNlRvIx6RkGt3ksGw6wMfMSpyWxTZon4RyPwYEEIrXISwBt4TlwgAQtBjzPki1nNiTzSM442EycX+TbcwxvfGyws+fnbz744SNRthxIgDEZG4hQD7KF6BgcBaNgFIyCkQsAb8o0mm8CgCoAAAAASUVORK5CYII=","orcid":"","institution":"Anhui University of Science and Technology","correspondingAuthor":true,"prefix":"","firstName":"Guangquan","middleName":"","lastName":"Xu","suffix":""},{"id":501221796,"identity":"b348fbaf-4491-4bf3-b9cf-68515ba306dd","order_by":2,"name":"Tingting Yang","email":"","orcid":"","institution":"Anhui University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Tingting","middleName":"","lastName":"Yang","suffix":""},{"id":501221797,"identity":"4af1e137-b412-493e-ad55-1eb209276d10","order_by":3,"name":"Haitao Zhang","email":"","orcid":"","institution":"Anhui University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Haitao","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2025-06-18 01:38:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6918019/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6918019/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s13146-026-01261-x","type":"published","date":"2026-04-02T15:58:32+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":89378558,"identity":"bf6f61fe-d33f-4880-b4ba-e71663e942cb","added_by":"auto","created_at":"2025-08-19 11:32:54","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":480576,"visible":true,"origin":"","legend":"\u003cp\u003eKarst geological map of bedrock in Huainan area\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/593379ca32b59825e0167860.png"},{"id":89378556,"identity":"3045f15e-c793-4bb7-ba56-fc5d060999c0","added_by":"auto","created_at":"2025-08-19 11:32:54","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":518348,"visible":true,"origin":"","legend":"\u003cp\u003eGeological profile of typical section in Huainan\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/09d00d15d7b8a6924a49edd0.png"},{"id":89378561,"identity":"99680529-e907-4e81-b7e4-2a459a104baa","added_by":"auto","created_at":"2025-08-19 11:32:54","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":908405,"visible":true,"origin":"","legend":"\u003cp\u003eKarst collapse types under the different dip angles\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/d2d3aee6a5a1e71ef994cd08.png"},{"id":89380054,"identity":"e07fcfbd-093f-4d21-bc59-7845bda89aab","added_by":"auto","created_at":"2025-08-19 11:40:54","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":592060,"visible":true,"origin":"","legend":"\u003cp\u003eStructural models of numerical simulation about karst collapse\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/c46f6cf220114fba88dc404f.png"},{"id":89378560,"identity":"ed75ec98-07e0-4183-be78-d34801c74570","added_by":"auto","created_at":"2025-08-19 11:32:54","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":353125,"visible":true,"origin":"","legend":"\u003cp\u003eCorresponding surface displacements under different variation of water levels during karst collapse\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/0c156c1398b5e280ffa68796.png"},{"id":89380057,"identity":"9f78f8f7-6321-4d1d-af8f-954ee0c33fe1","added_by":"auto","created_at":"2025-08-19 11:40:55","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":448194,"visible":true,"origin":"","legend":"\u003cp\u003eCorresponding curves of displacement in each observation piont under different dewatering conditions\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/d7b05025a2e1d520ca153867.png"},{"id":89381999,"identity":"73da679c-7ef4-4884-b93c-931a870721d1","added_by":"auto","created_at":"2025-08-19 12:04:55","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":357073,"visible":true,"origin":"","legend":"\u003cp\u003eCorresponding curves of effective stress along vertical direction of karst cave under different variation of water levels\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/6f3817e987e20ef5131d2e2a.png"},{"id":89380063,"identity":"656cafb1-3c34-43d2-a2d3-9ccc7a7d20e3","added_by":"auto","created_at":"2025-08-19 11:40:55","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":374547,"visible":true,"origin":"","legend":"\u003cp\u003eCorresponding to nephograms of surface displacement under different load changes\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/d8039a223b5716f1712bd60e.png"},{"id":89381582,"identity":"460471e8-0600-46d3-bece-336bbd43f10a","added_by":"auto","created_at":"2025-08-19 11:56:55","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":332048,"visible":true,"origin":"","legend":"\u003cp\u003eCorresponding to displacement in each observation point along vertical direction of karst cave under increased load conditions\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/f58fc5adb58dba094e4c1ce1.png"},{"id":89378577,"identity":"5ca77817-f4cb-4bba-9e29-e5796269ac76","added_by":"auto","created_at":"2025-08-19 11:32:55","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":336651,"visible":true,"origin":"","legend":"\u003cp\u003eCorresponding to curves of effective stress along vertical direction of karst cave under increased load conditions\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/f3de0312d23957e9a72f4fc8.png"},{"id":106343936,"identity":"b011aacb-da44-489a-8097-81139ae08e14","added_by":"auto","created_at":"2026-04-07 16:10:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4622362,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6918019/v1/40a8f80f-b436-4009-9ec6-ed7c7b0f1de1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Different Types and Formation Mechanisms of Karst Collapse in Huainan City","fulltext":[{"header":"Introduction","content":"\u003cp\u003eKarst collapse is the phenomenon in which the covered carbonate rocks undergo chemical dissolution, physical deformation, and mechanical collapse under the influence of physical, chemical, and gravitational processes, resulting in surface deformation and collapse disasters（Zhang et al.2005;Yan 2022;Liu et al.2020）. Due to\u0026nbsp;the\u0026nbsp;differences in lithology, structure and attitude of strata, hydrogeological conditions, and induced factors, the location and timing of karst collapses occur\u0026nbsp;with\u0026nbsp;a certain degree of randomness, suddenness, and unpredictability, which\u0026nbsp;brings both opportunities and challenges for the prevention of karst\u0026nbsp;hazards\u0026nbsp;and also has\u0026nbsp;being\u0026nbsp;attracted widespread attention at home and abroad\u0026nbsp;(Xu\u0026nbsp;2024;Si\u0026nbsp;2023). Over the years,\u0026nbsp;relatived surveys and\u0026nbsp;research\u0026nbsp;are about\u0026nbsp;the formation conditions of\u0026nbsp;karst\u0026nbsp;collapse, including\u0026nbsp;strata, structure, meteorology, and hydrodynamics,\u0026nbsp;as well as human activities. Focusing on the distribution patterns and developmental characteristics of karst collapses, as well as their\u0026nbsp;induced\u0026nbsp;mechanisms, several theories have been successively proposed, including the theory of suffosion, chemical dissolution, pressure\u0026nbsp;effect, vacuum suction theory, and hydraulic fracturing theory\u0026nbsp;(Xu et al.1981;Wang et al.2017;Hu\u0026nbsp;2022;Wu etal.2021;Caupin et al.2006;Mcmanus et al.1997;Standing et al.2013;Thomas et al.1999;Standing et al.2013;Li et al.2024;Luo et al.2021;Chen et al.2014;Che et al.2021;Zhang et al.2022;Qin et al.2021).\u0026nbsp;Furthermore, simulations and analyses have been carried out\u0026nbsp;by the\u0026nbsp;FLAC\u003csup\u003e3D\u003c/sup\u003e and LBM-DEM software, combined with elastoplastic theory and variable saturation seepage theory, to\u0026nbsp;restore\u0026nbsp;the evolution process of karst collapse and reveal the mechanisms of collapse formation\u003csup\u003e\u0026nbsp;\u003c/sup\u003e(Xiong et al.2022;Tao et al.2024;Li et al.2022;Yu et al.2020;Chen et al.2024;Xiong et al.2022).\u003c/p\u003e\n\u003cp\u003eThe study area is located in the southern part of the Huainan Coalfield, at the southern margin of the North China Block. Due to the influence of\u0026nbsp;multi-period\u0026nbsp;geological tectonic movements and long-term dissolution and erosion\u0026nbsp;from\u0026nbsp;surface water and groundwater.The development form of karst has diversity and complexity.(Xuan et al.1999;Li et al.2018;).\u0026nbsp;Karst collapses have occurred\u0026nbsp;due to the dewatering\u0026nbsp;during\u0026nbsp;mining activities. Karst geological surveys\u0026nbsp;results show that internal factor is closely related to\u0026nbsp;lithology, stratigraphic combination, geological structure, and hydrogeological conditions,\u0026nbsp;and the main\u0026nbsp;induced\u0026nbsp;factors\u0026nbsp;is involved to the variation of\u0026nbsp;groundwater level\u0026nbsp;during\u0026nbsp;drainage and overlying loads\u0026nbsp;(Li et al.2018;Huang et al.2012;Chen et al.1990;\u0026nbsp;Yu et al.\u0026nbsp;2024;\u0026nbsp;Jia et al.\u0026nbsp;2021).\u003c/p\u003e\n\u003cp\u003eAbove-mentioned studies have provided some reference for the prevention and control of karst collapse disasters in Huainan (Feng 2021;Zhang 2021). However, with the successive closure of coal mines along the Bagong Mountain-Shungeng Mountain area and the acceleration of urbanization, the hydrogeological conditions of karst have been changed. Therefore, it is necessary to study the distribution patterns and types of collapse furtherly, \u0026nbsp;systematically analyzing influened factors and formation mechanisms which will provide a basis for the ecological restoration of closed mines and the prevention and control of karst collapse disasters during urban construction.\u003c/p\u003e"},{"header":"1. Background of geology","content":"\u003cp\u003e\u003c/p\u003e\u003cp\u003eHuainan ctiy is located near Huai River in Anhui province, which is characterized by subtropical and warm temperate hills and plains. In the exposed carbonate rocks, the water from atmospheric precipitation along the surface and infiltrates into the underground carbonate strata, recharging the shallow karst aquifer covered by loose layers. Weathering and erosion occur continuously when groundwater infiltrate through channels such as faults, fractures, and dissolution pores in the shallow carbonate aquifer(Filipović et al.2025). This is especially evident in the Ordovician and Cambrian karst aquifer systems covered by the sediment of Quaternary system, where strong flow zones are formed along the breccia zones of faults(Kaufmann et al. 2016). Therefore, there is a close hydraulic connection between the precipitation and shallow karst groundwater (Li et al.2024). The study area includes Shungeng Mountain and Bagong Mountain, where the Archean Huoqiu Group, Proterozoic Qingbaikou System and Sinian System, Paleozoic Cambrian, Ordovician, Carboniferous, and Permian strata, as well as Mesozoic Triassic strata are exposed from south to north, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eFrom the tectonic perspective, the study area is located on the southern margin of the North China Coalfield, bounded by the Fufeng Reverse Fault to the north, and the Fuli Normal Fault to the south, the Changfeng Fault to the east, extending to the Fengtai County town to the west. Under the action of thrust and compression structures, Shungen Mountain and Bagong Mountain are distributed along the near EW and NNW, respectively, which have been influenced by multi-period tectonic geological processes, including Caledonian uplift, Indosinian compression, and Yanshanian extension, leading to the development of faults of different ages. The main faults include the Fufeng reverse fault, the Shungen Mountain reverse fault, and the Fuli normal fault, which are the boundary faults of the thrust sheet. In addition, small faults trending in the SN and NNW have developed within the thrust sheet (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eShungeng Mountain is composed of two segments: Jiulonggang-Quanshan and Luoshan, influenced by the thrust tectonic activity, which strata have been overturned. From east to west, the dip angle of the strata decreases progressively from 85\u0026deg; to 20\u0026deg; along the strike. Only in the area of Jinjialing-Quanshan are the Carboniferous and Permian coal-bearing strata exposed as intercalations. The Luoshan segment is composed of the Archean Huoqiu Group, the Upper Proterozoic Qingbaikou System and Sinian System, and the Mesozoic Triassic strata, and also is a thrust nappe block. The Luoshan thrust block exerts a compressive thrust effect on the block on the east side of Bagong Mountain,inducing the Ordovician, Carboniferous, and Permian strata in the Liyingzi area to be overturned.\u003c/p\u003e\u003cp\u003eIn the Bagong Mountain segment, the strata trend is nearly along the NNW and dip to the northwest, which is divided into two geological blocks by the Shanwangji Fault: the Liyingzi-Xinzhuangzi block and the Shanwangji Fault-Fengtai block. The former consists of normal monoclinic strata with a dip angle of about 20\u0026deg;,and the latter's strata with a dip angle of about 80\u0026deg;. The main faults are distributed along the NNE and NW (Li et al.2018). The karst strata are covered by Quaternary loose sediments with a thickness of 0\u0026ndash;15 m, where are prone to karst collapse (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe development of dissolved pores and fractures leads to some differences in the storage capacity and permeability, especially in fault zones where tectonic karst brecciations is well-developed, such as the Shanwangji Fault zone and the Shungeng Mountain Fault zone.And with the influence of dewatering from mining activities and domestic water use by residents, the groundwater level in the shallow karst areas has dropped significantly.This has resulted in the depression cones of groundwater, which has accelerated the dissolution and suffosion in the shallow carbonate rock strata inducing karst collapse (He et al. 2018;Zhou et al. 2016;Li et al.2015;Liu et al.2014; Sevil et al. 2017).\u003c/p\u003e"},{"header":"2 Characteristics of karst collapse","content":"\u003cp\u003eSince 1952, a total of 131 karst collapses have been occured which appeared in clusters, mainly along the Bagong-Shungeng Mountain Fengtai County, Kongji, Tubazi, Liyingzi, Jiulonggang, and Datong.These karst collapses are situated in the carbonate rock strata of the Majiagou Formation in the Ordovician System. The investigated results are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eThe karst collapses with circular, elliptical, and elongated shapes ,develop along the trend of strata and fault structures, and also are filled with loose sandy soil under the influence of changes in the shallow groundwater level and urban construction(Guo et al.2024).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eStatistics of karst collapse investigation in Huainan\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"10\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eNames of karst collapse clusters\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eLocation\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eNumbers\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eStratum\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eGeometric shape\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e\u003cp\u003eGeometric dimensions/m\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003edepth/m\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"1\" nameend=\"c10\" namest=\"c10\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eLength/m\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eWidth/m\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eRadius/m\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"1\" nameend=\"c10\" namest=\"c10\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFengtai County seat collapse cluster\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFengtai County seat\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMajiagou Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eNear-elliptical or circular\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.1\u0026thinsp;~\u0026thinsp;6.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e3\u0026thinsp;~\u0026thinsp;5.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c10\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eKongji collapse cluster\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eKongji\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMajiagou Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eElongated shape\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e14\u0026thinsp;~\u0026thinsp;16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.5\u0026thinsp;~\u0026thinsp;3.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c10\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eTubazi collapse cluster\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBagong Mountain soap factory\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMajiagou Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCircular, elliptical, and elongated shape\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3\u0026thinsp;~\u0026thinsp;95\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3\u0026thinsp;~\u0026thinsp;15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e3\u0026thinsp;~\u0026thinsp;7.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c10\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDaguadi\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMajiagou Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eBead-like and circular\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e5\u0026thinsp;~\u0026thinsp;20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3\u0026thinsp;~\u0026thinsp;9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3\u0026thinsp;~\u0026thinsp;10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e1\u0026thinsp;~\u0026thinsp;12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"1\" nameend=\"c10\" namest=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLiyingzi collapse cluster\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eChunshenjun Mausoleum\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMajiagou Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCircular, elliptical, and elongated shape\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e8\u0026thinsp;~\u0026thinsp;10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2\u0026thinsp;~\u0026thinsp;5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e0.2\u0026thinsp;~\u0026thinsp;1.6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003eShungeng Mountain collapse cluster\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eQishanji Pear Orchard\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e66\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eZhangxia Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eIrregular elliptical shape\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u0026thinsp;~\u0026thinsp;60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0\u0026thinsp;~\u0026thinsp;40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e0.1\u0026thinsp;~\u0026thinsp;6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDatong Cement factory\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMajiagou Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCircular or other shapes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0\u0026thinsp;~\u0026thinsp;20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0\u0026thinsp;~\u0026thinsp;10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e0.2\u0026thinsp;~\u0026thinsp;10\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eWuceng\u0026thinsp;~\u0026thinsp;Dongshan mountain\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eZhangxia Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCircular\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c10\" namest=\"c6\"\u003e\u003cp\u003e0.2\u0026ndash;0.5 0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eShengjiagang\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMajiagou Formation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCircular\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e/\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e1.5\u0026thinsp;~\u0026thinsp;13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e\u003cp\u003e1\u0026thinsp;~\u0026thinsp;2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"3 Discussion","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Influencing factors of karst collapse\u003c/h2\u003e\u003cp\u003eThe formation of karst collapse is not only related to strata structure, lithology, and geological structure, but also to the thickness of covered clay and sand layers and the groundwater hydrodynamic conditions (Liu et al.2014;).\u003c/p\u003e\u003cp\u003eSurvey results have revealed that the Zhangxia Formation of the Cambrian System mainly consists of dolomitic oolitic limestone and bioclastic limestone, while the Majiagou Formation of the Ordovician System is predominantly composed of calcareous dolomite and dolomite. According to the drilling data, the karstification rate of the Majiagou Formation ranges from 10.3\u0026ndash;17.16%, and that of the Zhangxia Formation of the Cambrian System ranges from 9.3\u0026ndash;13.3% (Huang et al.2012;He et al.2018;Han et al.2021). Among 131 karst collapses ,16.0% occur in the Zhangxia Formation, and 74.81% occur in Majiagou Formation, mainly distributed in the limestone and dolomitic limestone strata.\u003c/p\u003e\u003cp\u003eDue to the influence of overturning tectonic movements, the strata had been tilted and overturned, with the development of normal and reverse faults of different types and scales, with high-angle tension fractures and fault breccia zones which provide pathways for groundwater flow, and which also is one of the important controlling conditions for the formation of karst collapses (Liu et al.2014;Ding et al.2020;Jin et al.2018;Xu et al.2004). Especially, in Shungengshan reverse fault, and Shanwangji normal fault zone, and other smaller fault systems, dense fracture networks often form. These networks enhance the dissolution and piping effects of groundwater on carbonate strata, also accelerating the formation process of karst collapses.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Induced types of karst collapse\u003c/h2\u003e\u003cp\u003eThe karst in the southern part of the Huainan coalfield belongs to the typical northern karst. There are many commonalities in the formation conditions of karst collapse from the outcrop area to the covered area, but there are still some differences in the induced mechanisms. Based on the formation conditions and induced factors, the karst collapses are divided into the following four types.\u003c/p\u003e\u003cp\u003e\u003cem\u003e(1)The type of karst collapse induced by dewatering during mining\u003c/em\u003e\u003c/p\u003e\u003cp\u003eThe strata are affected by the thrust structure. The attitude of strata outcrops changes in different geological blocks and can be divided into steeply dipping, gently dipping, and overturned. The statum dip angles not only alters the groundwater flow patterns, but also plays a significant controlling role in the development of karst. The groundwater flow patterns from horizontal to vertical direction have caused the change in the karst development morphology from horizontal layer shapes to vertical cylindrical shapes. Consequently, the plane shape of karst collapses has also been shifted from elliptical to circular. During the concentrated dewatering of the Carboniferous limestone aquifer during coal mining, the run off zones of groundwater were formed along the fault zone around the mines, which caused a static imbalance between the collapsing soil and rock mass and the groundwater, thereby inducing karst collapses. According to the different strata dip angles, three types can be distinguished as follows:\u003c/p\u003e\u003cp\u003e(1)The type of karst collapse in steeply dipping strata\u003c/p\u003e\u003cp\u003eThe karst collapses in steeply dipping strata is mainly distributed in the Datong and Kongji ,which is influenced by the Shungengshan thrust nappe structure and the Shanwangji tension fault zone. Due to the large dip angles of strata, the development of karst is concentrated in the intersections of structural fractures and solution fissures that are perpendicular or oblique to the strata trend, and during the dewatering and pressure reduction by action of dewatering, the pore water pressure of the soil and rock is reduced. The loose sand and soil filling in the caves are disturbed, and the destruction of original stress balance leads to the formation of karst collapse.(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea、b)\u003c/p\u003e\u003cp\u003e(2)The type of karst collapse in gently dipping strata\u003c/p\u003e\u003cp\u003eThe karst collapse in gently dipping strata mainly occurs in the Tubazi area. Influenced by tectonic activity, vertical or oblique fractures develop along the bedding planes of strata and are filled with Quaternary loose materials. During the dewatering, the groundwater exerts the disturbed effect on the loose soil,and soil caves continue to expand. The effective stress carried by the soil particle and the pore water pressure gradually decrease. Under the action of the overlying strata load, karst collapse is formed.(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec、d).This type of collapse appears as a string of beads in plan view, and the collapse area is relatively large.\u003c/p\u003e\u003cp\u003e(3)The type of karst collapse in overturned strata\u003c/p\u003e\u003cp\u003eThese karst collapse are mainly distributed in the Liyingzi area. Influenced by the Shungengshan thrust nappe, the strata are overturned at the fault bend and develop multiple vertical or oblique tension fractures along the bedding planes.These fractures are filled with loose Quaternary sediment at their intersections.Due to infiltration from atmospheric precipitation and groundwater flow, a unified karst groundwater flow field is formed in the Ordovician and Carboniferous systems.Later, dewatering and pressure reduction during mining activities cause the loose soil and water mass to become unbalanced, leading to collapse.(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ee、f).This type of collapse appears as elongated shapes in plan view, with narrow width ranges.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003e(2) The type of karst collapse induced by changes in gravity load\u003c/em\u003e\u003c/p\u003e\u003cp\u003eThese karst collapses induced by changes of gravity load due to urban construction mainly occur in the Political New District of Fengtai County. The Quaternary loose strata overlie the karst strata of Cambrian and Ordovician, and influenced by the Shiwangji normal fault and long-term weathering and erosion. The degree of cave development is relatively higher. In recent years, with the intensification of urban construction, the increased overlying load has altered the pore water pressure and effective stress of the soil and water in the caves,which is loss of balance in the rock-soil-water system, ultimately resulting in karst collapse(Lyu et al. 2024; Zhang et al. 2022).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e3.3 The formation mechanism of karst collapse\u003c/h2\u003e\u003cp\u003eIn order to further reveal the formation mechanism of karst collapse in shallowly covered carbonate area, and predict karst collapse disaster caused by the above two induced factors, FLAC\u003csup\u003e3D\u003c/sup\u003e was used to simulate two scenarios respectively: one is the decline of karst groundwater level caused by dewatering and pressure reduction during mining ; the other is the disturbance of the stress balance states due to the increase in overlying load by urban construction, which causes instability and subsequent ground karst collapse.\u003c/p\u003e\u003cdiv id=\"Sec7\" class=\"Section3\"\u003e\u003ch2\u003e3.3.1 Design of Karst collapse model\u003c/h2\u003e\u003cp\u003e(1)Geological model of karst collapse\u003c/p\u003e\u003cp\u003eBased on previous drilled geological data and field karst geological surveys, the lithostratigraphic structure mainly consists of two layers in the karst collapse area. The first is a loose sandy and soil layer, with the upper segment being clay and the lower segment a confined sandy aquifer. The second is a carbonate karst strata, developing caves at different depths that are filled with overlying loose sandy soil and form close hydraulic connections with groundwater. According to the relationship between the loose aquifer and karst collapse, a model of the overlying loose aquifer and underlying karst collapse aquifer was established(Wang et al,2022). The model dimension is 80m \u0026times; 80m \u0026times; 120m, where the thickness of the overlying sandy soil layer is 10m and 20m, respectively, and the thickness of the underlying carbonate rock layer is 30m and 60m, respectively. The cave within the model is 10m wide and 30m high, as shown in Fig.\u0026nbsp;4.\u003c/p\u003e\u003cp\u003e(2)Boundary conditions of the model\u003c/p\u003e\u003cp\u003eIn order to analyze the deformation and failure process of the potential collapse soil layer caused by internal stress changes induced by gravity and groundwater level fluctuations, the influence of horizontal tectonic stress can be neglected. A vertical loading method (0 kN to 0.9 kN) is adopted, and the variation in the groundwater level is within the range of 5 m to 30 m. Unidirectional constraints are applied to the lateral boundaries and the ground surface boundary of the model, while the model surface is set as a free boundary.\u003c/p\u003e\u003cp\u003e(3)Parameters\u003c/p\u003e\u003cp\u003eThe elastoplastic models built should match the Mohr-Coulomb criterion and Darcy's law. During the simulation process, the deformation parameters of the rock and soil mass are represented by the shear modulus (G) and the bulk modulus (K). The deformation modulus is converted into the shear modulus and bulk modulus using Equations (1) and (2):\u003c/p\u003e\u003cp\u003e\u003cimg src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAN4AAACsCAYAAAAUjRJ9AAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAAFiUAABYlAUlSJPAAABZ7SURBVHhe7d19TBv3/Qfwt39/RjYMHX+EsE2LPYKQpoSHOtUqVCUYAgQqRVkJD9vopDZUSaaJxGiP3dJ0WlMoDtKkspKQalMkOEK0ScXAqiwkDWgPafGZrBIKCLN/sFHFKcM+7d/v/vhxN/z1AwY/3Nl8XtL90e/3zqmjvP29+z6diTHGQAjJqP/jCwgh6UfBI0QHFDxCdEDBI0QHFDxCdEDBI0QHFDxCdEDBI0QHFDxCdEDBM7BAIACbzQaTyZTQ4Xa7+Y8gBkXBM7CioiKsrKzg1q1bAACr1Qq/3w/GmHYsLS3B4XBAEAQUFxfzH0EMioKXBQ4ePAgAqK6uRlFRUVhdSUkJ7ty5g7Nnz6KkpCSsjhgXBS8LPHv2DADQ0tLCV2mKi4thNpv5YmJQJlqdYGyKouDMmTNYXV3F3Nyc1uIFAgHMzs7i3Llz/CUkC1CLZ3DLy8vwer04fPgwLBaLVj4yMoIDBw6EnUuyBwXP4GZmZiDLMhobG7VbSVEUMTY2hqqqKv50kiUoeAamKAqmp6cBAD09PdqwQXt7O/Ly8sJaQJJdKHgGpt5mOhwOhEIhMMYQCoXQ2dlJnSlZjoJnYNFuM81mM1paWuL2cBLjo+AZlHqbKQgCampqwury8vJosDzL0XCCQUmShLq6OuTn54cNI5DcQC2eQam3mdFmq2zndru1OZqKoqC2thYmkwm1tbVQFIU/nRgEBc+AtvdmxnuWkyQJ77zzjjascOnSJTQ2NoIxhsbGRly6dIm/hBgEBc+ARFHEgwcPYk58liQJXV1dqKysRFlZGYqKiiBJEhYXF9HR0QEA6OjogN/vRyAQ4C8nBmDY4K2vr2NgYAClpaVhS18aGxshSRIURcGvf/3rnLqdcrvdMJlMOH/+PABAlmVUVlZGLP+prKzErVu3IAgCuru7AQBra2thY3sWiwWMMczPz4f9GcQYDBc8RVHQ1dWFoqIiLC4uQhTFsGUwr732Gurq6mCxWHDgwIGcGstqbm4O+647HRsbG6ioqAC2JlLT2F72MFTwJEnCN77xDfzxj3/E5OQkbt68qf3DUrW1teH+/fsQBAGlpaVhdYRkC8MET+0+B4D79+/j9OnT/CmakpISnD17luYqblNaWoq1tbWcuvXOZYYIXiAQwKuvvgpZlvGzn/0sopWL5mtf+xrNVdymuLgYwWAQoVAI2JpuFgwG6cfJoAwRvJGREfh8PjgcDrz55pt8dQSz2Yxf/vKX9DyzTUVFBcrKyjAyMgJsjQO2trbGHQMk+tE9eIFAAIODgwAQNieR7N4HH3yA6elpmEwmPH36FE6nkz+FGITuwZufn4fP54s6JzEZLpcrohs+3uFyufiPyDpmsxl/+ctfwBjDH/7wB76aGIjuwVP3E8nPz9c29eGp41v8YbPZYg4QO53OiO73eAe1DiSTdA/e06dPASBia4Pt1PGtiYkJCIIAABgdHcXKygo9w5CspHvwjh49yhfFpE6fcjgcaG5u5qvThm9p6Yh9kMToHjx1EHx1dVXrCo8l2sLQTOBvS+mIfZDE6B68qqoqWK1W+Hw+rSs8mngLQ6PZj50rJHsYYiGs2+3GK6+8AqvVij//+c9Rd0SmhaEkl+je4mGr82R0dBSbm5v49re/DVEUI6Y+JbowlJBsYIgWT7W+vo7R0VF8+OGHWFpa0soFQYDdbserr76KpqammMMOhGQLQwVvvxgeHkZVVVVCc1KNRpIkzM/P44033uCryC4Y4lZzv1AUBdeuXcva0GFrTujBgwdpwkGSKHgZdPXqVZjN5qwNnaq5uRmHDh2inuAkUPB2SVEUOJ1OFBYWwmQyobCwEAMDAxGdQTy3242FhYWoqy/W19dx9+5dtLW1obCwEJIk8acYTkdHBwYHB+kttHvFSMJCoRBzOBwMQMTR2dnJn65Rr5uYmOCrmMfjYQ0NDayhoYEBYIIgMI/Hw59mSP39/czhcLBQKMRXkR1Qi7cLQ0NDaGpqCnuPwdtvvw0AmJycjNlSPXr0CF6vN+qOYRUVFZiensZHH30Eq9XKVxtaTU0NvF4vHj16xFeRnfBJJLvX2dkZs6VSW7udWgb1vFifE4/f72d2u33X1yUr0e9GIlGLlyLl5eVRZ9yob/zJxR3AzGYziouL4fV6sby8zFeTOCh4SZIkCV9++SXu3LkTNVjqjJvdrMJIt0AgAJvNFnU9o7oNfKKdPEePHoUsy1hbW+OrSBwUvD1SFAUDAwNoa2vDu+++G3Mam7reMFe3IlS/1/j4OF9F4qDg7YHb7YbFYsGVK1ewtLSEuro6iKLInwZFUfZNS0BbC+4OBW8P1BXxHo8Hdrsdsiyjvb09YkwrFAphdXU15jsQckFxcbG2KwBJHAUvCRUVFZiZmYHD4QAydLsVbZ3hoUOH8Nlnn0V9z8Jrr73Gf0RaJLKQmfwPBS9JZrM57MUh6b7diraJk9/vh91uh8fjiaij3caMiYKXAuoq+lwcMiDpQcFLISMNGWRavF3iSCQKXgqo76BTXwqpslgsOHz4sGHHuTY3N7G+vh5WFgqFEAwGw8riWVtbgyzLfHFaiKKIhYUFvnjX+vr64PP5+OKMouAlSB10LiwsDNuaQhRFXL9+Hffu3YsYy1NndiRieXkZq6urkGU5Yy+TlGUZH3/8sfZdpqamcPnyZa1OfWa9ffs2d2WkdN5my7IMu92Of/7znzh27BhfvWv19fU4deoUpqam+KrM4eeQkdiuXLkStiLhyJEj7MaNG3HnKU5MTDAArL+/n69iLM6Kh93M2dztXE31/NbWVu3Ps9vtbHJykjHG2KeffsoEQdDK/X4//xGa/v5+BiDqyotUWFlZYQUFBWx0dJSvimp2dpb19vbyxRG8Xu+uPjfVKHhp5vF4mCAIcZcNZdpugxpPvAniqfDCCy+wDz/8kC+OUF9fz2w2GwOQUPDYtvB5vV6+Ku3oVjPNSkpKUF5enpGhhkStr69jc3OTL941dWZOrAniyerr64MgCFEXD/Peeust/P73v4fNZuOrYjp27BiuX7+O73znOxl7TlVR8NJMHecz0gz+VHWIqCsvuru70/J899577+Gtt97ii6Oqrq5GdXU1vvnNb/JVcamhvnfvHl+VVhS8DDhx4gTKy8sxMzPDV+lifHw8JT2tMzMzKC8vx4kTJ/iqpM3NzeH58+eorq7mq1Kuq6sLw8PDfHFaUfAyQG31BgcHI5bh6KGlpSXp+aPqlvrpau3++te/or6+ni9Oi5deegmff/45X5xWFLwMaW5uxsWLF+O+HyJTmpubsbGxkdRuZ0NDQ2hsbMzoW5tyCQUvg5xOJ/x+f8QqhmwjSZK221q6vPTSS3jy5AlfnDMoeBnmcrnwn//8xzAdLbv1+PFjzM/P4+rVq3xVSpWVleH58+cZmWESDAZRUFDAF6cVBU8H586dS0v3eya8/PLLGdm+XRAEXLhwAf39/XxVyrndbpw6dYovTisKHjGsnp4eiKIYdXV/qszNzeF3v/sdfvjDH/JVaUXBI4ZltVrx8OFDXLx4EUNDQ3x10mRZxg9+8AP8/Oc/z8iwxXYUPGJox44dw8OHDzE8PIyLFy/y1WF8Ph+ePHmi7ewWjyzLaGhowKlTp/Cb3/yGr047ek0XyQqyLOP27duor6+PukLBZDLxRcD/LwLgi7CwsICTJ0/iwoULuoQOFDyyH/X19cUMcKZQ8AjRAT3jEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCh4hOqDgEaIDCl6WCgQCsNlsMJlMCR1ut5v/CKIjCl6WKioqwsrKCm7dugVsvbbY7/eDMaYdS0tLcDgcEAQBxcXF/EcQHVHwstzBgwcBANXV1SgqKgqrKykpwZ07d3D27FmUlJSE1RF9UfCy3LNnzwAALS0tfJWmuLgYZrOZLyY6ojfCZjFFUXDmzBmsrq5ibm5Oa/ECgQBmZ2dx7tw5/hJiENTiZbHl5WV4vV4cPnwYFotFKx8ZGcGBAwfCziXGQsHLYjMzM5BlGY2NjdqtpCiKGBsbQ1VVFX86MRAKXpZSFAXT09MAgJ6eHm3YoL29HXl5eWEtIDEeCl6WUm8zHQ4HQqEQGGMIhULo7OykzpQsQMHLUtFuM81mM1paWuL2cBJjoOBlIfU2UxAE1NTUhNXl5eXRYHkWoOGELCRJEurq6pCfnx82jECyB7V4WUi9zYw2W2U7t9sdNkdTURTU1tbCZDKhtrYWiqKEnU8yh4KXZbb3ZsZ7lpMkCe+8807YsMKlS5fQ2NgIxhgaGxtx6dKlsGtI5lDwsowoinjw4EHMic+SJKGrqwuVlZUoKyvTWkRJkrC4uIiOjg4AQEdHB/x+PwKBAPcJJBMMEbxYS1xsNpv2D8PlckXUu1wu/qNyltvthslkwvnz5wEAsiyjsrIy4u+ksrISt27dgiAI6O7u1q5fW1sLG9+zWCxgjGF+fl47h2SOIYKnLnHp7+8HAAiCgMnJSaysrGi/2G+++aa2xOXGjRsIBAJwOp3cJ+Wu5ubmsCU/Ox0bGxuoqKjQrn/27BmN7xmIIYLHa2pqwunTp7X/VhQFLpcLVqsVf/vb33D58mVtOQwh2chQwXv69CnAdRosLy+jpaUFpaWluHnzJq0r26PS0lKsra1RT6ZBGCZ4gUAAc3NzsFqtWk+cKIr40Y9+hN/+9rdoa2vjLyG7UFxcjGAwiFAoBGz9oAWDQZpMrRPDBG9+fh4+n08bm3K5XPjss88wPj5OrVwKVFRUoKysDCMjI8DWWGBra2vccUCSPoYJ3vj4OLC1d0hrayuw1ZNJnQGp88EHH2B6ehomkwlPnz7dV51ThsMMwO/3M6vVygAwAKyzs5M/Zdf6+/u1z0vk6O/v5z+CkLQxxFxNt9uNV155BUeOHIEsy5BlGf39/fSLTHKWIW411dvMrq4u3L9/H4IgoKenh/aCJLmLbwIzTb3NFASBeTwexrbdJlqtVub3+/lLdMHfmtKRnmO/0L3FU3szy8vLtd5Lp9OJzs5O+Hw+fP/73zfE2BM/M4SO9Bz7he7BU/eF3L6SGls9cA6HAw8ePNjTLPpoczvjHftp3ifRn66dK4FAANXV1djc3MT9+/fD5hZur/f5fNTZQnKKbi2eoii4efMmfD4f8vPzo47Xra+vY3NzE9jaSevatWuGuO0kJGn8Q18mxBpjczgcLBQKxT0HNOZGcoCut5r7mSiKyMvLC1uFkev243eORbdbzf1seHgYAPbdP8C2tjYsLi5SRxYFL/NcLhc2Nzf37WoLp9MJv9+/78NHwdslRVHgdDpRWFgIk8mEwsJCDAwMJNTpI0kSxsbGtH1PeOvr67h79y7a2tpQWFgISZL4U9Ii2ndyOp0Jfae96OnpwdjYWMa+nyHxD30ktlAoxBwOR0RnDxKY2K1eG6tjyOPxsIaGBtbQ0MAAhM3kSad43ymdM4c6OzvDOtP2G2rxdmFoaAhNTU1h7yp4++23AQCTk5Nxf8EfPXoEr9cbsfOzqqKiAtPT0/joo49gtVr56rQZGhpCMBjE48ePI76Tz+fDT3/6U/6SlOju7obX68WjR4/4qv2BTyLZvc7Ozh1bqM7OzoRaELUF2unzUiEUCrHz589H/X9K93xZdY7uTncKuYpavBTZPteUJ0kSJicnd9z5OdNCoRBqa2uj/j/V1NRAEAS+OGUsFgsOHz68451CrqLgJUmSJHz55Ze4c+dO1Nk32NrTUpZlHD16lK/SVVFR0Y6va+bfNqvugbp9z1OVukV8Ih1DZrMZxcXFkGUZa2trfHXOo+DtkaIoGBgYQFtbG959992orYZKXW+YTdQfi+7u7pg/KMlSf4iy8e8nWRS8PXC73bBYLLhy5QqWlpZQV1cHURT504CtgKq/6KWlpXy1YY2Pj8PhcODEiRN8Vcqofx/7cdtBCt4eqLs6ezwe2O12yLKM9vb2nFkxL0kS/v73v+P9999PW2u331HwklBRUYGZmRk4HA4gxi1TKBTC6uoqX5y0dK03VBQF7733HlwuV8QyrXRZXV3V9vvcLyh4STKbzdrLQTJ5y+R0OiNWb8c7El3LODQ0hOPHj6O5uZmvIilEwUuBqqoqWK3WrH8piMvlgt/vTzikZO8oeCkUbbhAHa8yOlEUdZu8zA9ZGInP58PFixf54qRR8FJAfcdcrMnPRieKIv70pz/h2rVrfBWmpqaitoCbm5tYX18PKwuFQggGg2FlepNlGX19fXxxwqxWK15++WX84he/4KuSQsFLkDpwXFhYCFEUtWc5URRx/fp13Lt3L+pYnjpQjG0bO8WzvLyM1dVVyLKckZdGiqKI9vZ23L17FxaLJaJTpqmpCSdPnuQvgyzL+Pjjj7W/h6mpKVy+fFmrU593b9++zV35P+rfR7pu0RcWFvDiiy/i61//Ol+1K21tbVhZWcHU1BRftXf8HDIS25UrV8Jm7x85coTduHFjxxn2ExMTO65giLVKIJ1zNkdHRyP+PP7g52r6/X5mt9tZa2urdo7dbmeTk5OMMcY+/fRTJgiCVh5vnqc6H3RiYoKvStrk5CQrKChgXq+Xr9JsbGyw3t5eZrPZGABWUFDALly4wDY2NvhT2crKCisoKIhatxcUvAxQJwTnwjIYNXip+DFIZHL5XqghiRc6xhh74YUXWG9vrxam2dlZVlBQwOrr6/lTGWOMXbhwgfX29vLFe0LBy5BEVycYncfjYUeOHEk6LOlcnVBfX79jQNQWkafeBaysrPBVzOv1Rr1mL+gZL0NaWlrg8/ky8tyWTuoczmSpWzduf/tvKiwsLODJkyd4/fXX+aowX3zxBZ4/fx7x3PbVr34VAOD3+8PKAeDYsWPA1vNssih4GXLixAk4HI6os1uyyfj4eEpWFMzMzKC8vDzlc0E/+eQTHD9+fMclTa+//jp6e3u1ji/eoUOH+CIAwPHjx/HFF1/wxbtGwcsQs9mM999/H4uLixHLabJJS0sLBEGI+Q82EYFAAGNjY2mZCzozMxNzlf92giDgxz/+sdaKqUZGRlBfXx9zF4Cqqip4PB6+eNcoeBlUUVGBX/3qV+jv7+erskZzczM2NjaSmsc5MjKC1tbWpD4jHRYWFiCKIgYHB/kqTX5+Pv7973/zxbtGwcuw5uZmHDp0SJcZIkYgiiLy8/OjDsqnQk1NzZ5aJFmW8ZOf/AQPHz6M2dpha+LAV77yFb541yh4OnA6nSgrK4u5hi9XqZ0Sb7zxBl+VMt/61rfw+eef88VxybKM7373u+jt7Y249eTNz8+jsrKSL949vpuTkGxns9nY6OgoXxzVxsYGq6+v33HMT2Wz2bTJAsmg4JGck8isFbZD6GZnZ/kiGscjJJ7Tp09jcHAQJ0+exNzcHF+tiXV7GWuc7u7duynbZ5TeFkRy1tTUFL73ve9hcHAw4l0VfX19+Ne//hWxoiQYDOLq1asYHh4OC6Qsy3jxxRfxj3/8Y8cxwkRQ8EhOU98mzA8RNDQ04JNPPgkr246PRVtbG86cORMR4L2i4BGyA1EU8fjx44jwJoOe8QiJQ5bllIcO1OIRog9q8QjRAQWPEB38F5DikyXVxTp+AAAAAElFTkSuQmCC\" style=\"width: 116px; height: 89.8739px;\" width=\"116\" height=\"89.8739\"\u003e\u003c/p\u003e\u003cp\u003eIn the above equations, \u0026micro; is the Poisson's ratio of the overlying rock and soil mass, and \u003cem\u003eE\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e is its deformation modulus.\u003c/p\u003e\u003cp\u003e(4)Simulation scenarios\u003c/p\u003e\u003cp\u003eBased on the soil layer, stratum structure as well as the hydrogeological conditions of karst, one simulation scenario is to model karst collapse induced by dewatering and depressurization during mining, with simulations carried out for the decline of groundwater level. The second, without considering changes of the water level, and only taking into account the increase of the overlying load due to urban construction, and the simulation is conducted according to the application of different loads.\u003c/p\u003e\u003cp\u003e(5) Model establishment and discretization\u003c/p\u003e\u003cp\u003eThrough the analysis of the above-mentioned models and scenarios, the strata parameters are determined based on geological drilled data(Xu et al.2004). A numerical model of karst collapse, such as multi-layer, has been established. The model structure consists of five parts(Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The model is designed with 157,378 grid points and a total of 255,056 grid units.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eMechanical parameters of different layers\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRegion\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDensity\u003c/p\u003e\u003cp\u003e(kN/m\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTensile strength\u003c/p\u003e\u003cp\u003e(kPa)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAngle of internal friction\u003c/p\u003e\u003cp\u003e(\u0026deg;)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCohesion(kPa)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eBulk Modulus\u003c/p\u003e\u003cp\u003e(MPa)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eShear Modulus\u003c/p\u003e\u003cp\u003e(MPa)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eclay layer1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2400\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e70\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e13.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e57.6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003esandy soil layer2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2300\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e73.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eKarst area\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2300\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e9.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e73.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRock layer1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2600\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e170\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e112\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRock layer2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2900\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e130\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e136\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section3\"\u003e\u003ch2\u003e3.3.2 The mechanism of karst collapse induced by dewatering\u003c/h2\u003e\u003cp\u003eUsing the above-mentioned model, the process of dewatering karst groundwater under coal mine mining conditions was simulated. The overall changes in surface displacement, as well as the variations in effective stress and displacement over time at corresponding points in the karst strata, were analyzed when the groundwater level dropped to 5 m, 10 m, 15 m, 20 m, and 25 m, as shown in Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e5\u003c/span\u003e, \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e6\u003c/span\u003e, and 7.\u003c/p\u003e\u003cp\u003eThe simulation results indicate that affected by the dewatering during mining and the domestic water use of urban residents, the groundwater levels in different aquifers continuously decline which leads to a reduction in the pore - water pressure within the rock and soil mass, causing changes in the stress of the caves. As a result, the stability of the sandy soil filling the karst caves is disturbed,and the original stress balance is broken, and ultimately, the karst collapses have occurred.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\u003ch2\u003e3.3.3 The mechanism of karst collapse induced by overlying loads\u003c/h2\u003e\u003cp\u003eTo reveal the stress and strain conditions at different depths under various loading conditions within the potential karst collapse area, six probe points were set up along the vertical direction to obtain the deformation and force conditions at corresponding locations, as shown in Fig.\u0026nbsp;4(c).\u003c/p\u003e\u003cp\u003eThe simulation results show that the accumulated deformation near the top of the cave is relatively significant, and the settlement is positively correlated with the fixed load, showing a downward trend. As the fixed load increases from 0 kPa to 9 kPa, the surface settlement increases from 29.98 mm to 578.08 mm. The displacement of the two soil layers above the cave changes significantly with the fixed load, while the underlying rock layer is relatively stable with a small deformation. As the load increases, the nephograms of surface displacement and the curves of displacement and effective stress of corresponding points over time are shown in Figs.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e8\u003c/span\u003e, \u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e9\u003c/span\u003e, and 10.\u003c/p\u003e\u003cp\u003eThe above simulation indicates that the occurrence of karst collapse in urban construction is mainly due to the increased overlying load,which leads to the changes in the hydrostatic pressure stress of the soil-water body filling the karst caves and the effective stress of the rock and soil mass.This results in the imbalance of the rock-soil-water body filling the karst caves, and subsequently causing the collapse of the karst cave strata of the Cambrian and Ordovician systems covered by the Quaternary system.\u003c/p\u003e"},{"header":"4 Conclusion","content":"\u003cp\u003eThrough the investigation of karst collapses in Huainan city, the formation conditions, karst strata and patterns have been analyzed, and the formation process of karst collapses was revealed with a mechanistic perspective. The main conclusions are as follows:\u003c/p\u003e\u003cp\u003e\u003col\u003e\u003cli\u003e\u003cp\u003eInfluenced by thrust nappe tectonic movement, lithology of strata, atmospheric precipitation, and the thickness of loose cover, karst collapses are mainly distributed along the bedding direction, fault zones, shallow loose covered area, and urban construction zones. From the outcrop to the shallow burial area, karst collapses occur in the strata of the Cambrian Zhangxia Formation and the Ordovician Majiagou Formation, and the plane shapes of the collapses are mostly circular, elliptical, and strip.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eKarst collapses are formed along fault fracture zones of soluble rock strata, and carbonate strata covered by loose layers. According to the genesis and induced factors, the karst collapses can be divided into four patterns, namely ,steeply dipping, gently dipping, and overturned patterns, as well as karst collapse patterns related to gravitational load.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eDuring the process of groundwater level decline during dewatering and with increase of overlying load from urban construction, there are significant differences in the displacement and effective stress changes within the karst-soil-groundwater- internal structure. Therefore, the manifestation of karst collapse processes varies under different hydrogeological conditions and induced factors.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe areas around Fengtai County city, Bagong Mountain and Shungeng Mountain will still be the regions where karst collapses are likely to occur in the future. It is necessary to further monitor and prevent possible karst collapses to occur,focus on concealed areas of the groundwater recovery zones after the mines are closed and the urban construction areas, and carry out active and effective prevention measures.\u003c/p\u003e\u003c/li\u003e\u003c/ol\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eML wrote the main manuscript text, GX revised the manuscript text, TY prepared figures and tables, and HZ provided important materials. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e\u003cp\u003eThis paper is supported by the National Natural Science Foundation of China (No. 42172279) .The great supports from the Huaihe Energy Holding Group Co., Ltd. of China, and the State Key Laboratory of Anhui University of Science and Technology are greatly appreciated.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eZhang JG,2005.Karst process and its lmpact on construction stability of the slope terrain within muddy limestone in the Three Gorges region.J.Acta Geoscientica Sinica (06):565-569.\u003c/li\u003e\n\u003cli\u003eYan LBQ,2022.Characterization of Occurrences of karst collapses in Guilin and assessment of their future trend.D.Guilin University of Technology.\u003c/li\u003e\n\u003cli\u003eLiu CZ,Chen CL ,2020. Achievements and countermeasures in risk reduction of geological disasters in China.J. Journal of Engineering Geology 28( 2) : 375-383.\u003c/li\u003e\n\u003cli\u003eXu SL,2024.Analysis of the formation mechanism and prevention and control measures of karst collapse geological disasters in Suixi County, Huaibei City.J.Ground water 46(03):201-203.\u003c/li\u003e\n\u003cli\u003eSi ZY,2023.Brief Analysis of the Mutual Influence Relationship between Hydrogeological Conditions and Geological Disasters of Karst Collapse: A Case Study of the Panjia Laowu Area in Yueshan Town, Huaining County.J.Western Resources (02):103-105.\u003c/li\u003e\n\u003cli\u003eBouzerda M, Mehdi K, Boualla O, Fadili A, Najib S, Saied M,2024\u003cem\u003e.\u003c/em\u003e Inventory and geomorphological analysis of karstic collapse dolines in Sahel-Doukkala (Morocco). Carbonates Evaporites 39, 93. \u003c/li\u003e\n\u003cli\u003eXu WG,Zhao GR,1981.The implication of suction action for ground subsidence in karst mining areds.J.Geological Review (02):174-180+183.\u003c/li\u003e\n\u003cli\u003eWang F,Chai B,Xu GL,Chen L,Xiong ZT,2017.Evolution mechanism of karst sinkholes in Wuhan city.J.Journal of Engineering Geology 25(03):824-832.\u003c/li\u003e\n\u003cli\u003eHu CL,2022.Formation of karst collapse induced by combined action of water and gas mechanism research.D.Chongqing Jiaotong University.\u003c/li\u003e\n\u003cli\u003eWu YB, Yin RC, Lei MT, Dai JL, Jia L, Pan ZY, Ma X, Zhou FB,2021.Triggering factors and prevention-control countermeasures of karst collapses caused by tunnel construction in the Zhongliangshan area, Chongqing.J.Carsologica Sinica 40(02):246-252.\u003c/li\u003e\n\u003cli\u003eCaupin F, Herbert E,2006. Cavitation in water: a review.J. Comptes rendus - Physique 7(9-10):1000-1017.\u003c/li\u003e\n\u003cli\u003eMcmanus K J, Davis R O, 1997. Dilation-induced pore fluid cavitation in sands.J. G\u0026eacute;otechnique 47(1):13-177.\u003c/li\u003e\n\u003cli\u003eStanding J, Ghail R, Coyne D,2013. Gas generation and accumulation by aquifer drawdown and recharge in the London Basin.J. Quarterly Journal of Engineering Geology and Hydrogeology 46(3):293-302.\u003c/li\u003e\n\u003cli\u003eThomas M Tharp,1999. Mechanics of upward propagation of cover-collapse sinkholes.J].. Engineering Geology 52:23-33.\u003c/li\u003e\n\u003cli\u003eStanding J, Ghail R, Coyne D,2013. Gas generation and accumulation by aquifer drawdown and recharge in the London Basin.J. Quarterly Journal of Engineering Geology and Hydrogeology 46(3):293-302.\u003c/li\u003e\n\u003cli\u003eLi JT,Zhu K,Xiao XX,Yin Y,Liu H,Xu M,He ZP,2024.Development mechanism of covered karst collapses induced by groundwater drawdown.J.Carsologica Sinica 43(2):406-420.\u003c/li\u003e\n\u003cli\u003eLuo XJ,Luo C,2021.Three-Mechanism Theory (TMT) of karst ground collapse and its application.J.Carsologica Sinica 40(02):171-188.\u003c/li\u003e\n\u003cli\u003eChen LJ,Sun XL,Pi J,Wang C,Ou J,2014.Distribution characteristics and factors influencing karst collapse in Dachengqiao,Ningxiang,Hunan.J.Carsologica Sinica 33(04):490-497..\u003c/li\u003e\n\u003cli\u003eChe ZG,Liu H,Yu YX,2021.Study on geological conditions and formation mechanism of karst collapse in JiangdongVillage,Jinting Town,Suzhou City.J.East China Geology 42(01):85-92.\u003c/li\u003e\n\u003cli\u003eZhang ZS,2022.Origin and trend analysis of karst collapse in Huangqi and Haibei communities, Foshan City.J.Carsologica Sinica 41(6):880-894.\u003c/li\u003e\n\u003cli\u003eQin JW,Song GX,Pan GM,2021.Cause and law of karst collapse in the urban complex environment:An example of Beihuanxincun, Guigang City.J.Carsologica Sinica 40(02):230-237.\u003c/li\u003e\n\u003cli\u003eXiong QH,Gao X,Xu Q,Wang RQ,Li ZC,Tao L,2022.Dynamic evolution numerical model of cover-collapse sinkholes.J.Safety and Environmental Engineering 29(01):85-92.\u003c/li\u003e\n\u003cli\u003eTao XH,Ye M,Gong JS,Wang HS,Hu XY,2024.Analysis of the formation process of the covered karst ground collapse induced by groundwater changes based on the coupled LBM-DEM numerical simulation at micro scale.J. The Chinese Journal of Geological Hazard and Control 35(1): 124-131.\u003c/li\u003e\n\u003cli\u003eLi ZY,Lin LP,Li BH,2024.Numerical simulation of karst collapse in limestone mining areas based on FLAC3D.J.Scientific and Technological Innovation (22):33-36.\u003c/li\u003e\n\u003cli\u003eYu LH,Yan JL,Yu XJ,Hu ST,2020.Evolution and numerical simulation of karst caves based on FLAC3D.J.Ground water 42(04):55-57.\u003c/li\u003e\n\u003cli\u003eChen XJ,Xue MM,Song Y,2024.Influence of water level dropping rates on the collapse of karst soil caves.J.Carsologica Sinica 43(04):922-936.\u003c/li\u003e\n\u003cli\u003eXiong QH,Gao X,Tu J,Wang RQ,Yan EC,Li ZC,2022.Mechanism of soil - cave type karst collapse under negative pressure and its mechanical model.J.Yangtze River 53(09):163-168+180.\u003c/li\u003e\n\u003cli\u003eXuan J,Yang SL,1999.The basic features of kast collapse and preliminary study on their forming mechanism in the tubazhi district of huainan city.J.Geology of Anhui 9(4):301-306.\u003c/li\u003e\n\u003cli\u003eLi ZH,Xu GQ,Gao JL,Zhang HT,Yang TT,2018.Characteristics of karst development and collapse mechanism in Shungeng Mountain,Huainan,Anhui Province.J.The Chinese Journal of Geological Hazard and Control 29(2):86-93.\u003c/li\u003e\n\u003cli\u003eLi ZH,Xu GQ,Gao JL,Zhang HT,Yu ST,2018.Characteristics of structure and their influence on karstification in Huainan area.J.Coal Geology \u0026amp; Exploration 46(3):121-126.\u003c/li\u003e\n\u003cli\u003eHuang H,Yan JP,Piao CD,2012.Karst collapse distribution and land-use feasibility of shallow overburden type karst area in Datong District,Huainan City.J.Journal of Natural Disasters 21(2):112-117.\u003c/li\u003e\n\u003cli\u003eChen ZY,1990.Discussion about karstic surface collapses in Huainan mining area.J.Journal of Huainan mining institute 10(2):1-7.\u003c/li\u003e\n\u003cli\u003eYu XG,Wang SC,Su BC,Zhang WQ,2024.Exploration and prediction of high pressure dynamic water hidden collapse column in coal mines.J.Water Resources and Industry,31,100250. \u003c/li\u003e\n\u003cli\u003eJia, L., Meng, Y., Li, L. et al. A multidisciplinary approach in cover-collapse sinkhole analyses in the mantle karst from Guangzhou City (SE China).J.Nat Hazards 108, 1389\u0026ndash;1410 (2021). \u003c/li\u003e\n\u003cli\u003eFeng YW,2021.Distribution and genesis of karst collapse in Shandong Province.J.Carsologica Sinica 40(2):205-214.\u003c/li\u003e\n\u003cli\u003eZhang HT,2021.Formation Mechanism and Prediction of Ordovician Paleokarst in Huainan Coalfield.Huainan:Anhui University of science and technology.\u003c/li\u003e\n\u003cli\u003eIvona Ivkić Filipović, Nikolina Ilijanić, Slobodan Miko, Ozren Hasan, Dea Brunović, Branko Kordić, Uro\u0026scaron; Barudžija, Željka Sladović,2025.Late Quaternary geomorphology and sedimentary processes in the Prolo\u0026scaron;ko Blato karst wetland (Imotsko Polje, Croatia).J.Geomorphology.482,109765. \u003c/li\u003e\n\u003cli\u003eKaufmann G,Romanov D,2016.Structure and evolution of collapse sinkholes: Combined interpretation from physico-chemical modelling and geophysical field work.J. Journal of Hydrology,540:688-698. \u003c/li\u003e\n\u003cli\u003eHe B,Gao P,2018.Development characteristics analysis and prevention countermeasures of karst ground collapse in Jiulonggang area of Huainan City.J. Resources Information and Engineering 33(01):173-175.\u003c/li\u003e\n\u003cli\u003eZhou XP.Zhang CL,Ma JG,Liu MC,Ma L,Qian JZ,2016.Characteristics of multiple aquifers groundwater system in hugely thick Cenozoic stratum in Huainan.J.Journal of hefei university of technology(Natural Science) 39(12):1693-1697.\u003c/li\u003e\n\u003cli\u003eLi X,Xu GQ,Wang MH,Liu MC,Ma JG,2015.Groundwater and its influencing factors in panxie coal mine area.J.Coal Technology 34(01):182-184.\u003c/li\u003e\n\u003cli\u003eXu GQ,Sun FY,Liu LH,Li PQ,Wang MH,Liu MC,2016.Evolution process and prediction of karstic geologic abnormal bodies in Panxie coal mining area in Huainan.J.Coal Geology \u0026amp; Exploration 44(1):62-68.\u003c/li\u003e\n\u003cli\u003eLiu MC,Xu GQ,Liu LH,Li ZF,Dou CY,Jin XR,2014.Application of tracing test in detection of water inrushing channels in limestone aquifer.J.Coal Geology \u0026amp; Exploration 42(5):50-54.\u003c/li\u003e\n\u003cli\u003eSevil J, Guti\u0026eacute;rrez F, Zarroca M, Desir G, Carbonel D, Guerrero J, Linares R, Roqu\u0026eacute; C, Fabregat I,2017.Sinkhole investigation in an urban area by trenching in combination with GPR, ERT and high-precision leveling. Mantled evaporite karst of Zaragoza city, NE Spain.J.Engineering Geology,231:9-20. \u003c/li\u003e\n\u003cli\u003eGuo SL, Yan CH, Yu LC, Liu Y, Yan C,2024.Characteristics of shallow buried karst and its safety distance to tunnel in wuxi city, China.J.Quaternary Science Advances,13,100139. \u003c/li\u003e\n\u003cli\u003eHan QD,Luo XY,2021.Analysis on the formation mechanism and development process of karst collapses in Lijia Village, Gaoming District of Foshan City.J.The Chinese Journal of Geological Hazard and Control 32(4):56-64.\u003c/li\u003e\n\u003cli\u003eJin QZ,Ruan XY,Liu Lu,2021.Ground collapse in the Tubazi area of Huainan City and the ountermeasures.J.Geology of Anhui\u003c/li\u003e\n\u003cli\u003eDing TF,Wang MH,Zhao JF,2020.Genesis analysis and study on tectonic control on water of Huainan North China-type coal field.J.Coal Geology \u0026amp; Exploration 48(4):102-108.\u003c/li\u003e\n\u003cli\u003eJin QZ,Xu D,Liu L,2018.Geological disaster exploration report of Tubazi karst ground collapse in Bagongshan, Huainan City.R. Anhui Geological Environment Monitoring Station.\u003c/li\u003e\n\u003cli\u003eLyu XR, Ju BS , Wang B , Wu XW , Ding YZ,2024.Mechanism, mode, and prediction of karst caves collapse in the deep marine carbonate fracture-cavity reservoir.J.Marine and Petroleum Geology, 167,106978. \u003c/li\u003e\n\u003cli\u003eZhang K, Zheng WB, Liao ZY, Xie HP, Zhou CT, Chen SG,Zhu JB,2022.Risk assessment of ground collapse along tunnels in karst terrain by using an improved extension evaluation method.J.Tunnelling and Underground Space Technology,129,104669.\u003c/li\u003e\n\u003cli\u003eWang XM, Wang SM, Peng XY, Ma TY, Chen B,2022.Equivalent numerical simulation method and application in karst-induced collapse of overlying sandy stratum.J.Engineering Failure Analysis,137,106280. \u003c/li\u003e\n\u003cli\u003eXu GQ,Shen HZ.Analysis on the land collapse induced by pumping groundwater \u0026mdash;Huainan Coal Mine as an example.J.The Chinese Journal of Geological Hazard and Control 2004,15(4):67-71.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"carbonates-and-evaporites","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"caev","sideBox":"Learn more about [Carbonates and Evaporites](http://link.springer.com/journal/13146)","snPcode":"13146","submissionUrl":"https://submission.nature.com/new-submission/13146/3","title":"Carbonates and Evaporites","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Carbonate rock of Cambrian and Ordovician, karst collapse, induced factors, formation mechanism, Huainan city","lastPublishedDoi":"10.21203/rs.3.rs-6918019/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6918019/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eKarst collapses have been occured ,which brings potential geological hazard for the risk of construction of mining cities and the ecological environment restoration. By the methods of field geological survey, statistical analysis and numerical simulation methods, the characteristics and distribution of karst collapses have been investigated systematically along such areas as Shungeng Mountain, Liyingzi,Tubazi,and Fengtai County, and the formation conditions and types of karst collapse are discussed, and the formation mechanisms are simulated under different conditions.The results show that influenced by the combined actions of stratigraphy, lithology, geological structure and hydrogeological conditions, karst collapses mainly develop in the Ordovician and Cambrian strata covered with the unconsolidated sediments, which is distributed concentrately along the strikes of strata and near fault tectonic zones. Based on hydrogeological conditions, dip of strata, and induced factors, karst collapses can be classified into four types:steeply dipping, gently dipping, overturned under dewatering conditions, and the variable load of overlying soil. In order to understand the formation mechanism of karst collapses, FLAC\u003csup\u003e3D\u003c/sup\u003e software is used to simulate and analyze the variation about displacement and effective stress at different designed observed points ,along vertical cross section covered with unconsolidated sediments during the processes of dewatering in coal mines and urban construction. The study of formation process of karst collapse provides important guidance for the prevention and control of karst collapse disasters.\u003c/p\u003e","manuscriptTitle":"Different Types and Formation Mechanisms of Karst Collapse in Huainan City","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-19 11:32:50","doi":"10.21203/rs.3.rs-6918019/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"27249402926379327977265098412337401518","date":"2025-08-16T07:56:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"95182540896847482196455412179633565420","date":"2025-08-13T06:18:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"224936198426243608027501668143589540944","date":"2025-08-11T07:40:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-11T02:34:57+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-23T11:35:01+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-19T01:31:41+00:00","index":"","fulltext":""},{"type":"submitted","content":"Carbonates and Evaporites","date":"2025-06-18T01:29:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"carbonates-and-evaporites","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"caev","sideBox":"Learn more about [Carbonates and Evaporites](http://link.springer.com/journal/13146)","snPcode":"13146","submissionUrl":"https://submission.nature.com/new-submission/13146/3","title":"Carbonates and Evaporites","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"10e6207c-ddff-47fb-9a50-f21086d4af24","owner":[],"postedDate":"August 19th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-07T16:06:06+00:00","versionOfRecord":{"articleIdentity":"rs-6918019","link":"https://doi.org/10.1007/s13146-026-01261-x","journal":{"identity":"carbonates-and-evaporites","isVorOnly":false,"title":"Carbonates and Evaporites"},"publishedOn":"2026-04-02 15:58:32","publishedOnDateReadable":"April 2nd, 2026"},"versionCreatedAt":"2025-08-19 11:32:50","video":"","vorDoi":"10.1007/s13146-026-01261-x","vorDoiUrl":"https://doi.org/10.1007/s13146-026-01261-x","workflowStages":[]},"version":"v1","identity":"rs-6918019","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6918019","identity":"rs-6918019","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}