地震边坡失稳机理及稳定性分析

通过对汶川地震边坡调研,发现大量边坡破坏形式为坡顶拉裂、下部坡体剪切破坏。本文利用有限差分程序,从边坡土体的应力状态出发,通过监测边坡土体的状态、位移和剪应变增量变化等,分析了岩土体在静力、横向地震和耦合地震作用下的破坏过程,发现坡顶附近发生张破坏,以下部位发生剪切破坏,而非传统的地质工程观点——地震边坡破坏主要是地震惯性力造成的剪切破坏。并提出一种新方法——关键点相对位移法,来判断边坡的动力稳定性,数值模拟结果与已有研究成果及震后灾害调查结果具有良好的一致性。

FAILURE MECHANISM AND STABILITY ANALYSIS OF SLOPE UNDER EARTHQUAKE

Investigation of the slopes in Wenchuan earthquake shows that tension failures mostly appear in the slope crests,and shear failure in slope toe. Beginning with the stress state of soil,using the finite difference method,the failure process of slope is analyzed under the given conditions of static,horizontal and coupled earthquake by monitoring the changing of state,displacement,and shear strain increment. The calculated results indicate that the slope crest is tensile damage and shear failure appears in slope toe. It is different from the traditional opinion of geological engineering that slope damage under earthquakes is mainly shear failure due to seismic inertia force. A new method of the relative displacement of key points is put out to judge the dynamic stability. Numerical simulation results have good consistency with existing research results and postseismic investigation findings．