基于颗粒流方法的滑坡破坏机理与强度分析

西安科技大学 地质与环境学院,陕西 西安 710054

地质资源与地质工程; 新府山滑坡; 颗粒流方法; 破坏机理; 滑坡强度

Landslide failure mechanism and intensityanalysis based on PFC2D
ZHAO Zhou,WEI Jiang-bo

(College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,China)

geological resources and geological engineering; Xinfushan landslide; particle flow method(PFC2D); failure mechanism; landslide intensity

DOI: 10.13800/j.cnki.xakjdxxb.2018.0414

备注

滑坡变形破坏机理与强度研究是滑坡风险评估的一项关键内容。针对颗粒流方法在滑坡变形破坏力学机理分析及滑坡强度定量化研究中存在的问题,以府谷县新府山滑坡为研究对象,采用野外调查、勘察、室内实验等方法,对新府山滑坡的工程地质特征进行了分析,在此基础上基于PFC2D数值方法构建了滑坡颗粒流数值模型,模拟了滑坡从变形失稳到运动终止的动态过程,从变形特征和力学特征2方面分别论述了滑坡的变形破坏机理,并选择速度、动能、冲击力指标对滑坡冲击破坏强度的变化特征进行了分析。结果 表明,新府山滑坡的变形破坏机理表现为坡脚挤压—坡中牵引—坡顶拉张的力学过程; 滑坡运动特征表现为破坏的突发性与堆积的缓慢性; 以速度、动能指标为表征的滑坡强度在其破坏的初始阶段最高,然后逐渐变小; 以冲击力指标为表征的滑坡强度随坡脚距的增加而呈指数衰减特征。研究结果与滑坡变形破坏实际特征基本吻合,研究结论可为新府山滑坡防治提供参考,研究方法可为单体滑坡冲击破坏强度定量及对承灾体易损性定量评价研究提供借鉴。

Landslide deformation failure mechanism and intensity is a key content of landslide risk assessment.Aiming at the problems in mechanical analysis and quantitative evaluation of impact strength in landslide deformation and failure process,taking Xinfushan Landslide in Fugu County as the object,and using the methods of field investigation,exploration and laboratory experiments,the engineering geological characteristics of landslide was studied.The numerical model of Xinfushan landslide was constructed based on the Particle Flow method(PFC2D),and the dynamic process of landslide from deformation instability to movement termination was simulated.The deformation and failure mechanism of the landslide are revealed from the deformation characteristics and the mechanical characteristics,the variation characteristics of landslide intensity was analyzed using the indexes of velocity,kinetic energy and impact force.The results show that the failure mechanism of Xinfushan landslide is manifested by the mechanical process of compaction at the foot of the slope,the traction of the middle slope,and the extension of the top of the slope.The characteristics of landslide movement are sudden failure and slowness of accumulation.The index of velocity and kinetic energy reflects that the intensity of landslide is the highest in the initial stage of failure,and then decreases gradually.The landslide intensity represented by impact force index is exponentially attenuated with the increase of slope foot distance.The results are in good agreement with the actual landslide deformation and failure characteristics and can provide reference for the prevention and control of Xin Fu Shan landslide and for reference for the quantitative evaluation of the intensity of single landslide and its vulnerability.