基于Flac-3D的盐源县玻璃村滑坡变形破坏机理数值模拟

NUMERICAL SIMULATION OF DEFORMATION AND FAILURE MECHANISM OF BOLI VILLAGE LANDSLIDE IN YANYUAN COUNTY BASED ON FLAC-3D

2018年7月19日凌晨5点40分左右,四川省凉山州盐源县桃子乡玻璃村发生一起特大型滑坡地质灾害,为了查明其变形破坏机理,通过现场调查、室内外试验及数值模拟等方法,在查明滑坡地质背景基础上,对其发育特征进行分析,并基于Flac-3D有限元软件强度折减法计算滑坡天然及饱和工况下的稳定性系数。通过对比分析两种工况下塑性区及剪应变增量带的分布情况,揭示滑坡的变形破坏机制。研究结果表明:玻璃村滑坡为古滑坡的局部复活,天然工况下滑坡稳定性系数为1.08,处于基本稳定状态,饱和工况下滑坡稳定性系数为0.928,处于失稳状态;古滑坡在强降雨作用下失稳并受地形影响发生多级复合滑动,滑坡前缘至中部滑体具有牵引式特征,后缘滑体具有前缘临空牵引、后缘推移式特征。

At about 5:40 a.m.on July 19,2018,a huge landslide geological disaster occurred in Boli village,Taozi Township,Yanyuan County,Liangshan Yi Autonomous Prefecture,Sichuan Province.In order to find out its deformation and failure mechanism based on field investigation,indoor and outdoor experiments and numerical simulation,discussesing the characteristics of the landslide on the basis of identifying the geological background of the landslide,The strength reduction method of Flac-3 D finite element software was performed to calculate the stability coefficient of ancient landslide under natural and saturated conditions.Through the comparative analysis of the distribution of plastic zone and shear strain increment zone under two conditions,the failure mechanism of landslide was simulated.The results show that the Boli village landslide is a part of the ancient landslide.The stability coefficient of landslide under natural conditions is 1.08,which is basically stable;under saturated condition,the stability coefficient of landslide is 0.928,which is in the state of instability.The ancient landslide is unstable under the action of heavy rainfall,and multi-level composite sliding occurs under the influence of topography.The sliding from the front edge to the middle of the landslide has traction characteristics,and the sliding mass at the rear edge has the characteristics of front edge free traction and rear edge pushing.