汶川地震区东河口滑坡破坏机制FLAC模拟分析

Numerical analysis of the failure mechanism of the Donghekou rockslide in the Wenchuan earthquake region with FLAC

以汶川地震触发的东河口滑坡为典型案例,根据野外调查结果建立震前地质模型,将实测的汶川地震波作为动力输入,采用FLAC有限差分法对该滑坡分别进行了静力稳定性分析及动力稳定性分析。计算结果表明:竖向峰值加速度导致了边坡的稳定性系数大幅降低,对边坡的破坏起着不可忽视的作用;另外,竖向峰值加速度引起了边坡后缘大面积的拉张破坏,这正是汶川地震引起西南山区产生大量崩滑甚至岩土体"抛掷"现象的一个重要因素。

Taking the Donghekou rockslide triggered by the Wenchuan earthquake as a case study,the geological model before the earthquake was established based on field investigation.Using the real seismic wave on May 12,2008,the static and dynamic stability analysis of the Donghekou rockslide was carried out with the software FLAC.The results show that the vertical peak acceleration had led to significant reduction in the slope stability factors,as a result,it played an important role in the slope failure.In addition,large-scale tensile failure at the main scarp of rockslides occurred due to the peak ground acceleration,which was just the reason for the occurrence of a large number of rockslides and rockfalls and even for soil and rock masses ＂throwing out＂ in southwest areas triggered by the great Wenchuan earthquake.