某城市排土场边坡三维稳定性分析

Three-dimensional stability analysis of city waste dump slope

针对湖南某城市排土场在强降雨作用下可能诱发地质灾害的问题,设计了4种降雨类型,利用ANSYS软件建模功能,生成排土场稳定性计算模型。利用ABAQUS有限元分析软件进行了非饱和土流固耦合分析,将4种类型的降雨分别施加在排土场上,同时考虑土体的渗透系数受土的孔隙比和含水率的影响。通过监测有限元模型特征部位位移是否发生突增及塑形变形区是否贯通来判断排土场是否发生破坏,以数值计算是否收敛求解排土场的稳定性系数。分析结果表明:若当地降雨强度大于30.72 mm/h且持续时间超过30min时,排土场就有发生滑坡危险的可能,需要提前做好灾害评估和险情预防工作。

Considering the problems that it would induce disasters of the waste dump near a city under heavy rainfall,four kinds of heavy rainfalls were designed. Using modeling function of ANSYS software,a model for the waste dump stability was established. The ABAQUS finite element analysis software was utilized to analyze fluid-solid coupling of unsaturated soils. Four kinds of heavy rainfalls were imposed on the dump. also considering that the permeability coefficient of soil was influenced by soil porosity ratio and moisture content. By monitoring wheather there was an abrupt increase in displacement of characteristic places of finite element and whether plastic deformation area cuts through the dump,whether or not there was a failure of the risk was judged. Besides,whether the finite element numerical calculation was convergence was used to solve the factor of stability. The results showed that,the waste dump might slide in the case of rainfall intensity larger than 30. 72 mm/h and its duration longer than 30 minutes,this reminded the relevant departments to prepare for disaster assessment and risk prevention.