基于离散元的含软弱夹层岩质边坡滑移机理分析
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摘要
以苏州清明山滑坡为例,采用颗粒流软件PFC2D建立了滑坡体的二维数值模型,通过监测坡体表面不同部位的位移和应力变化情况,对边坡滑动的演化过程和破坏机理进行了详细的分析。数值试验结果显示该顺层边坡的失稳是一个渐进的过程,首先沿靠近坡面的一组软弱结构面发生滑动,下方滑床岩体在上覆滑体的挤压和摩擦作用下发生破碎,使滑动不断向深处发展。在前期形成的临空面和软弱结构面的共同影响下,滑坡后缘岩体产生一组近乎垂直的拉裂面,该竖向破裂面的存在有利于雨水入渗,进一步降低软弱夹层的抗剪强度参数,从而使边坡由小范围的崩塌破坏转为大范围的滑动破坏,属滑移-压致拉裂型滑坡。清明山滑坡滑移机理的研究对后续地质灾害治理有重要意义。
Taking the Qingming Mountain landslide in Suzhou as an example,a two-dimensional numerical model of the landslide body was established by using the particle flow code software PFC2 D. By monitoring the displacement and stress changes in different parts of the slope,the evolution process and the failure mechanism were analyzed. The numerical test results show that the maximum slip distance of the unstable block on the surface of the slope is 54. 18 m and the depth of the sliding surface is about 20 m. The sliding instability of the slope is a gradual process. Firstly,the landslide is a plane slip along the weak structural plane close to the surface of the slope,and the rock mass below it is crushed under the pressure and friction of the overlying body,the landslides develop to the deep. Under the combined effect of the free plane and the weak plane formed in the early stage,the vertical failure plane is produced in the trailing edge of the rock mass. The existence of the vertical failure plane helps to infiltrate the rainwater and further reduce the mechanical parameters of the weak structural plane,thus the small range of collapse damage changes to a wide range of sliding failure. The failure of this slope can be defined as sliding and compression cracking. The study on the sliding failure mechanism of Qingming Mountain landslide is of great significance for the subsequent geological disaster management.
Taking the Qingming Mountain landslide in Suzhou as an example,a two-dimensional numerical model of the landslide body was established by using the particle flow code software PFC2 D. By monitoring the displacement and stress changes in different parts of the slope,the evolution process and the failure mechanism were analyzed. The numerical test results show that the maximum slip distance of the unstable block on the surface of the slope is 54. 18 m and the depth of the sliding surface is about 20 m. The sliding instability of the slope is a gradual process. Firstly,the landslide is a plane slip along the weak structural plane close to the surface of the slope,and the rock mass below it is crushed under the pressure and friction of the overlying body,the landslides develop to the deep. Under the combined effect of the free plane and the weak plane formed in the early stage,the vertical failure plane is produced in the trailing edge of the rock mass. The existence of the vertical failure plane helps to infiltrate the rainwater and further reduce the mechanical parameters of the weak structural plane,thus the small range of collapse damage changes to a wide range of sliding failure. The failure of this slope can be defined as sliding and compression cracking. The study on the sliding failure mechanism of Qingming Mountain landslide is of great significance for the subsequent geological disaster management.
引文
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[19]朱永生,朱焕春,石安池,等.基于离散单元法的白鹤滩水电站复杂块体稳定性分析[J].岩石力学与工程学报,2011,30(10):2068-2075.ZHU Yongsheng,ZHU Huanchun,SHI Anchi,et al.Complicated block stability analysis of Baihetan hydropower station based on distinct element method[J]. Chinese Journal of Rock Mechanics and Engineering,2011,30(10):2068-2075.
[20]杨圣奇,黄彦华.双孔洞裂隙砂岩裂纹扩展特征试验与颗粒流模拟[J].应用基础与工程科学学报,2014(3):584-597.YANG Shengqi,HUANG Yanhua. Experiment and particle flow simulation on crack coalescence behavior of sandstone specimens containing double holes and a single fissure[J]. Journal of Basic Science and Engineering,2014(3):584-597.
[2]周健,王家全,曾远,等.土坡稳定分析的颗粒流模拟[J].岩土力学,2009,30(1):86-90.ZHOU Jian,WANG Jiaquan,ZENG Yuan,et al.Simulation of slope stability analysis by particle flow code[J]. Rock and Soil Mechanics,2009,30(1):86-90.
[3]李祥龙,唐辉明,胡巍.层面参数对顺层岩质边坡地震动力破坏过程影响研究[J].岩土工程学报,2014,36(3):466-473.LI Xianglong,TANG Huiming,HU Wei. Effect of bedding plane parameters on dynamic failure process of sliding rock slopes[J]. Chinese Journal of Rock Mechanics and Engineering,2014,36(3):466-473.
[4]胡训健,卞康,李鹏程,等.水平厚层状岩质边坡地震动力破坏过程颗粒流模拟[J].岩石力学与工程学报,2017,36(9):2156-2168.HU Xunjian,BIAN Kang,LI Pengcheng,et al.Simulation of dynamic failure process for horizontal thick-layered rock slopes using particle flow code[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(9):2156-2168.
[5]崔铁军,马云东,王来贵.地震所致露天矿坡破坏的模拟与治理研究[J].应用力学学报,2016,33(2):339-344.CUI Tiejun,MA Yundong,WANG Laigui. Simulation of earthquake stability for open-pit coal mine slope and treatment research[J]. Chinese Journal of Applied Mechanics,2016,33(2):339-344.
[6]贺续文,刘忠,廖彪,等.基于离散元法的节理岩体边坡稳定性分析[J].岩土力学,2011,32(7):2199-2204.HE Xuwen,LIU Zhong,LIAO Biao,et al. Stability analysis of jointed rock slopes based on discrete element method[J]. Rock and Soil Mechanics,2011,32(7):2199-2204.
[7]周喻,韩光,吴顺川,等.断续节理岩体及岩质边坡破坏的细观机制[J].岩石力学与工程学报,2016(a2):3878-3889.ZHOU Yu,HAN Guang,WU Shunchuan,et al. Meso failure mechanism of rock mass and slope with intermittent joints[J]. Chinese Journal of Rock Mechanics and Engineering,2016(a2):3878-3889.
[8]李新坡,何思明.节理岩质边坡破坏过程的PFC2D数值模拟分析[J].四川大学学报(工程科学版),2010,42(增刊1):70-75.LI Xinpo,HE Siming. Numerical analysis of the failure of heavily jointed rock slopes using PFC2D[J].Journal of Sichuan University(Engineering Science Edition),2010,42(S1):70-75.
[9] SCHOLTES L,DONZEF V. Modelling progressive failure in fractured rock masses using a 3D discrete element method[J]. International Journal of Rock Mechanics&Mining Sciences,2012,52(6):18-30.
[10] HUANG D,CEN D,MA G,et al. Step-path failure of rock slopes with intermittent joints[J]. Landslides,2015,12(5):911-926.
[11] LO C M,LEE C F,CHOU H T,et al. Landslide at Su-Hua highway 115. 9 k triggered by typhoon megi in Taiwan[J]. Landslides,2014,11(2):293-304.
[12]胥良,石豫川,柴贺军,等. K28边坡变形破坏机制的离散元模拟[J].水文地质工程地质,2003,30(3):51-54.XU Liang,SHI Yuchuan,CHAI Hejun,et al.Simulation for the deformation failure mechanism of the K28 slope with discrete element method[J].Hydrogeology&Engineering Geology,2003,30(3):51-54.
[13]崔铁军,马云东,王来贵.基于下落法的PFC3D岩土模型构建及应用[J].安全与环境学报,2016,16(3):130-134.CUI Tiejun,MA Yundong,WANG Laigui. Research and application of the PFC3Dgeotechnical model based on fall particles method[J]. Journal of Safety and Environment,2016,16(3):130-134.
[14]代远,倪小东,周仁.基于颗粒流的局部强度折减法在边坡稳定分析中的应用[J].科学技术与工程,2014,14(10):262-265.DAI Yuan,NI Xiaodong,ZHOU Ren. Application of local strength reduction method based on particle flow code in slope stability analysis[J]. Science Technology and Engineering,2014,14(10):262-265.
[15]岑夺丰,黄达,黄润秋.岩质边坡断续裂隙阶梯状滑移模式及稳定性计算[J].岩土工程学报,2014,36(4):695-706.CEN Duofeng,HUANG Da,HUANG Runqiu. Step-path failure mode and stability calculation of jointed rock slopes[J]. Chinese Journal of Rock Mechanics and Engineering,2014,36(4):695-706.
[16]季宪军,欧国强,杨顺,等.基于PFC3D黏性与无黏崩滑土体运动过程对比分析[J].四川大学学报(工程科学版),2013,45(增刊1):67-73.JI Xianjun, OU Guoqiang, YANG Shun, et al.Comparison analysis of the motion process about viscous and no-viscous landslip-collapse soil based on PFC3D[J]. Journal of Sichuan University(Engineering Science Edition),2013,45(S1):67-73.
[17]韩光,崔铁军,马云东,等.煤层自燃所致上覆露天矿复杂边坡破坏过程模拟与现象研究[J].应用力学学报,2016,33(3):535-540.HAN Guang,CUI Tiejun,MA Yundong,et al. Research on the phenomenon and failure process simulation of open-pit slope in coal spontaneous combustion[J].Chinese Journal of Applied Mechanics,2016,33(3):535-540.
[18]朱雷,黄润秋,严明,等.基于裂纹扩展模式的岩质斜坡阶梯状滑移破裂机制研究[J].岩土工程学报,2017,39(7):1216-1224.ZHU Lei,HUANG Runqiu,YAN Ming,et al. Step-path failure mechanism of rock slopes based on crack coalescence modes in rock mass[J]. Chinese Journal of Rock Mechanics and Engineering,2017,39(7):1216-1224.
[19]朱永生,朱焕春,石安池,等.基于离散单元法的白鹤滩水电站复杂块体稳定性分析[J].岩石力学与工程学报,2011,30(10):2068-2075.ZHU Yongsheng,ZHU Huanchun,SHI Anchi,et al.Complicated block stability analysis of Baihetan hydropower station based on distinct element method[J]. Chinese Journal of Rock Mechanics and Engineering,2011,30(10):2068-2075.
[20]杨圣奇,黄彦华.双孔洞裂隙砂岩裂纹扩展特征试验与颗粒流模拟[J].应用基础与工程科学学报,2014(3):584-597.YANG Shengqi,HUANG Yanhua. Experiment and particle flow simulation on crack coalescence behavior of sandstone specimens containing double holes and a single fissure[J]. Journal of Basic Science and Engineering,2014(3):584-597.