A numerical study of the toppling failure of an anti-dip layered rock slope based on a cohesive crack model
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摘要: 反倾层状岩质边坡的倾倒破坏是一种常见的地质灾害。为探究开挖条件下反倾层状岩质边坡的倾倒破坏机制以及层间剪切强度、岩层厚度因素对破坏特征的影响，利用ABAQUS有限元软件，建立黏聚力裂缝模型（Cohesive Crack Model，CCM），基于连续-离散方法，经参数标定和对比，建立反倾层状岩质边坡CCM，采用开挖并增重的方式诱发边坡倾倒破坏。数值模拟结果与古水水电站坝前倾倒变形体离心模型试验结果基本一致，验证了CCM的正确性。进一步，基于以上参数及模型，研究了反倾层状岩质边坡的破坏演化过程和应力分布特征，并探讨层间剪切强度对边坡倾倒破坏特征的影响。结果表明：坡体前缘首先发生局部折断，后缘出现明显拉裂缝，反倾岩层由下往上依次折断直至倾倒体中部（一级破裂面）。随后，坡体前缘的表层岩层被挤出，形成二级破裂面，最后一级破裂面扩展至坡体后缘，形成连通宏观的破裂面。最后，二级破裂面扩展至坡体中部，边坡完全倾倒破坏；破裂面基本沿层间法向应力峰值位置连线发育；层间剪切强度对边坡倾倒破坏特征具有显著的影响，随着层间剪切强度的增大，岩层初始折断位置逐渐降低，垮塌范围逐渐减小，破裂面倾角增大；坡体层厚越大，一级破裂面分布越深，垮塌区范围越大，坡体滑动的整体性越强。研究成果可为反倾层状岩质边坡倾倒破坏的分析和监测提供有效计算方法及依据，为此类滑坡灾害的防治提供一定参考。Abstract: The toppling failure mechanism of an anti-dip layered rock slope is a kind of common geological hazard. In order to explore the toppling failure mechanism of an anti-dip layered rock slope and the influence of interlayer shear strength and rock thickness on the failure characteristics under the condition of excavation, based on the continuous-discrete method, the finite element cohesive crack model (Cohesive Crack Model, CCM) is established by ABAQUS. Through parameter calibration and comparison, the CCM of an anti-dip layered rock slope is established, and the slope toppling failure is induced by excavation and weight increase. The numerical results are basically consistent with the centrifugal model test results that are based on the toppling deformable body in front of the dam of Gushui Hydropower Station, which verifies the correctness of the CCM. Furthermore, the failure evolution process and stress distribution characteristics of the anti-dip layered rock slope are studied, and the influence of inter laminar shear strength on the toppling failure characteristics of the slope is discussed. The results show that the front edge of the slope is partially broken at first, and obvious tensile cracks appear at the back edge, and the anti-dip rock layer breaks from bottom to top until the middle of the dumping body (first-order fracture surface), and then the surface layer of the front edge of the slope is extruded to form a second-order fracture surface. The last first-order fracture surface extends to the back edge of the slope to form a connected macroscopic fracture surface, the second-order fracture surface extends to the middle of the slope, and the slope is completely toppled and destroyed. The fracture surface basically develops along the position of the peak value of the interlayer normal stress and the inter laminar shear strength has a significant influence on the toppling failure characteristics of the slope. With the increase of the inter laminar shear strength, the initial breaking position of the rock layer become lower, the collapse range decreases gradually, and the angle of the fracture surface increases. With the increase of the layer thickness of the slope, the distribution of the first-order fracture surface deepens, the range of the collapse area increases, and the integrity of the slope slip is enhanced. The research results provide an effective calculation method and basis for the analysis and monitoring of the toppling failure of reverse-dip layered rock slopes and provide some references for the prevention and control of such landslide disasters.
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[1] SIOBERG J. Analysis of failure mechanism in high rock slope[C]//VOUILIE G,BEREST P. Proceeding of the 9th International Congress on Rock Mechanics. Paris:Taylor and Francis Group,1999:127-130.
[2] 谭维佳. 三峡库区反倾层状内嵌岩梁式岩质岸坡失稳机理和防治研究[D].西安:长安大学,2015.[TAN W J. A study of the instability mechanism and failure control of the anti-dip stratified rock slope with embedded rock beam in the Three Gorges Reservoir Region[D]. Xi'an:Chang'an University,2015.(in Chinese)]
[3] 王章琼,晏鄂川,刘骏,等.湖北鹤峰红莲池铁矿反倾岩坡崩塌破坏特征及形成机理分析[J].中国地质灾害与防治学报,2016,27(3):7-13.[WANG Z Q, YAN E C, LIU J, et al. Characteristics and mechanism of the rock fall at Honglianchi iron mine in Hefeng,Hubei Province[J]. The Chinese Journal of Geological Hazard and Control,2016,27(3):7-13.(in Chinese)]
[4] 刘云鹏,邓辉,黄润秋,等.反倾软硬互层岩体边坡地震响应的数值模拟研究[J].水文地质工程地质,2012,39(3):30-37.[LIU Y P, DENG H, HUANG R Q, et al. Numerical simulation of seismic response of anti-dumping rock slope interbedded by hard and soft layers[J]. Hydrogeology & Engineering Geology,2012, 39(3):30-37.(in Chinese)]
[5] 黄波林,陈小婷,彭轩明.三峡库区巫山县廖家坪危岩体倾倒机制数值模拟分析[J].水文地质工程地质,2008,35(5):24-27.[HUANG B L, CHEN X T, PENG X M. Liaojiaping dangerous rockmass toppling numerical analysis in Wushan County in the Three Gorges Reservoir Region[J]. Hydrogeology & Engineering Geology,2008,35(5):24-27.(in Chinese)]
[6] 王章琼,晏鄂川,尹晓萌,等.层状反倾岩质边坡崩塌机理研究:以湖北鹤峰红莲池铁矿边坡为例[J].中南大学学报(自然科学版),2014,45(7):2295-2302.[WANG Z Q, YAN E C, YIN X M, et al. Study on collapse mechanism of anti inclined rock slope:A case study of Honglianchi Iron Mine slope in Hefeng, Hubei Province[J]. Journal of Central South University (Science and Technology),2014,45(7):2295-2302.(in Chinese)]
[7] GU D M, HUANG D. A complex rock topple-rock slide failure of an anaclinal rock slope in the Wu Gorge,Yangtze River,China[J].Engineering Geology, 2016,208:165-180.
[8] ALZOUBI A K, MARTIN C D, CRUDEN D M. Influence of tensile strength on toppling failure in centrifuge tests[J]. International Journal of Rock Mechanics and Mining Sciences, 2010, 47(6):974-982.
[9] 王霄,陈志坚,徐进鹏,等.似层状岩质边坡倾倒变形破坏过程数值模拟[J].水文地质工程地质,2018,45(1):137-143.[WANG X, CHEN Z J, XU J P, et al. Numerical simulation of deformation and failure process of a toppling-sliding rock slope with a quasi-lamellar structure[J]. Hydrogeology & Engineering Geology, 2018, 45(1):137-143.(in Chinese)]
[10] 代仲海,胡再强,尹小涛,等.工程荷载作用下缓倾角反倾似层状岩质边坡变形稳定性分析[J].岩土力学,2018, 39(增刊1):412-418.[DAI Z H, HU Z Q, YIN X T, et al. Deformation stability analysis of gentle reverse inclined layer-like rock slope under engineering load[J]. Rock and Soil Mechanics,2018,39(Sup1):412-418.(in Chinese)]
[11] 王宇,李晓,王梦瑶,等. 反倾岩质边坡变形破坏的节理有限元模拟计算[J].岩石力学与工程学报,2013,32(增刊2):3945-3953.[WANG Y, LI X, WANG M Y, et al. Failure mechanism of topping rock slope using jointed finite element simulation method[J].Chinese Journal of Rock Mechanics and Engineering,2013, 32(Sup2):3945-3953.(in Chinese)]
[12] 陶志刚,张海江,尹利洁,等.基于FDEM的戒台寺古滑体开裂破坏过程数值模拟[J].水文地质工程地质,2017,44(3):105-112.[TAO Z G, ZHANG H J, YIN L J, et al. Numerical modeling of cracking for the Jietai temple ancient landslide with the combined finite-discrete element method[J]. Hydrogeology & Engineering Geology,2017,44(3):105-112.(in Chinese)]
[13] 陈小婷,黄波林.FEM/DEM法在典型柱状危岩体破坏过程数值分析中的应用[J].水文地质工程地质,2018, 45(4):137-141.[CHEN X T, HUANG B L. Application of the FEM/DEM method to numerical analyses of the failure process of representative pillar-shape dangerous rock mass[J]. Hydrogeology & Engineering Geology, 2018,45(4):137-141.(in Chinese)]
[14] DUGDALE D S. Yielding of steel sheets containing slits[J].Journal of the Mechanics and Physics of Solids, 1960,8(2):100-108.
[15] BARENBLATT G I. The mathematical theory of equilibrium cracks in brittle fracture[J]. Advances in Applied Mechanics, 1962, 7:55-129.
[16] JIANG H X, MENG D G. 3D numerical modelling of rock fracture with a hybrid finite and cohesive element method[J]. Engineering Fracture Mechanics, 2018,199:280-293.
[17] JAIME M C D, ZHOU Y N, LIN J S, et al. Finite element modeling of rock cutting and its fragmentation process[J].International Journal of Rock Mechanics and Mining Sciences,2015,80:137-146.
[18] WANG H Y. Numerical modeling of non-planar hydraulic fracture propagation in brittle and ductile rocks using XFEM with cohesive zone method[J].Journal of Petroleum Science and Engineering,2015,135:127-140.
[19] 郑达,王沁沅,毛峰,等.反倾层状岩质边坡深层倾倒变形关键致灾因子及成灾模式的离心试验研究[J].岩石力学与工程学报,2019,38(10):1954-1963.[ZHENG D, WANG Q Y, MAO F, et al. Centrifuge model test study on key hazard-inducing factors of deep toppling deformation and disaster patterns of counter-tilt layered rock slopes[J]. Chinese Journal of Rock Mechanics and Engineering,2019,38(10):1954-1963.(in Chinese)]
[20] XIE D, WAAS A M. Discrete cohesive zone model for mixed-mode fracture using finite element analysis[J]. Engineering Fracture Mechanics, 2006, 73(13):1783-1796.
[21] YAO Y. Linear elastic and cohesive fracture analysis to model hydraulic fracture in brittle and ductile rocks[J]. Rock Mechanics and Rock Engineering, 2012, 45(3):375-387.
[22] 蔡静森,晏鄂川,王章琼,等.反倾层状岩质边坡悬臂梁极限平衡模型研究[J].岩土力学,2014,35(增刊1):15-28.[CAI J S, YAN E C,WANG Z Q, et al. Study of cantilever beam limit equilibrium model of anti-dip layered rock slopes[J]. Rock and Soil Mechanics,2014, 35(Sup1):15-28.(in Chinese)]
[23] 位伟,段绍辉,姜清辉,等.反倾边坡影响倾倒稳定的几种因素探讨[J].岩土力学,2008,29(增刊):431-434.[WEI W, DUAN S H, JIANG Q H, et al. Research on some factors influencing the toppling stability in anti-inclined slope[J]. Rock and Soil Mechanics,2008,29(Sup):431-434.(in Chinese)]
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