凤凰山边坡自重作用下破坏模式的数值模拟分析

Study on failure mode analysis of Fenghuangshan's landslides under the action of gravity with numerical methods

北川县擂鼓镇凤凰山滑坡为由"5·12"地震诱发的大型滑坡。通过对该滑坡的地质调查研究,总结了该滑坡的地质特征;通过Midas/GTS建立复杂坡面的三维地质模型,运用FLAC3D的强度折减法进行模拟计算,分析滑坡在自重作用下的应力场和位移场,研究潜在的破坏区及破坏模式。分析可知,在自重情况下,滑坡上部坡体对下部坡体产生推力,在滑坡前缘易出现推移式破坏。滑坡中上部主要为"压-剪"破坏模式,采取减轻滑坡后缘坡体重量的措施有利于滑坡的稳定。

＂5 · 12＂ earthquake induced the huge landslide called Fenghuangshan＇s landslide in Leigu town Beichuan County.Based on the geological survey,summarized the geological characteristics of the landslide.The software Midas/GTS is used to establish 3D geological model with complex surface.And simulating calculation of the landslide using FLAC3D,analyzes the stress field and deformation field of the landslide under self weight,and studies the potential failure zone and the failure mode.The results show that the higher part of the slope thrust on the lower part under self weight.It is easy to produce thrust load-caused failure in the lower of landslide.The main landslide failure mode is ＂pressure-shear＂ failure in the upper part of slope.Taking measures to reduce the landslide slope body weight is conducive to slope stability.