基于参数反演的保扎滑坡变形破坏机理研究

DEFORMATION MECHANISM OF BAOZHA LANDSLIDE WITH PARAMETRIC BACK ANALYSIS

大型复杂滑坡的复活变形机理研究,是目前滑坡地质灾害研究热点之一。针对恩施地区典型大型复杂滑坡-保扎滑坡,在系统研究其工程地质条件的基础上,分析了该滑坡的形成机制。建立二维计算模型,利用Flac软件,依据钻孔位移监测数据,通过位移反分析反演岩土体参数。对滑坡天然状态、河流不同下切深度进行了三种工况的模拟分析,结果表明:①保扎滑坡为牵引式滑坡。滑坡发育于志留系易滑岩组,滑坡形成的诱发因素是前缘老沟河的不断侵蚀下切与掏蚀,滑塌变形不断向中后部发展,从而引发整体滑动。②目前影响保扎滑坡变形与稳定性的主要因素为滑坡前缘河流下切及降雨;③保扎滑坡目前处于整体稳定状态。随着河流下切深度的增加,该滑坡将产生渐进式牵引破坏。建议对滑坡前缘进行治理。

The reactive mechanism of large landslide is complicated and is a key point of landslide research.The Baozha landslide is a typical large landslide in Enshi.Its stability is urgent to be evaluated in order to keep safety for people.Thid paper is based on the engineering geological condition investigation and analyses the formation mechanism.A 2D model is developed.With the FLAC software and based on the borehole displacement data,this paper inverses the rational calculation parameter of the soils and rocks forming the landslide.Considering landslide natural state and river trenching,three-simulations are done.The results show the following three points：（1）Baozha landslide is a pulling landslide.It is developed in easy-sliding strata-sandstone and muddy stone of Silurian System.Laogou river erosion and rainfall are the main induction factor.The slope front edge failed at the beginning.Then the deformation developed to middle and back of the slope.At last,the landslide happened.（2） at present,the main factors that influence the deformation and stability of the landslide are the Laogouhe river cutting and rainfall.（3）the Baozha landslide is stable now.With the river cutting deeper,this landslide is possible to have a progressive failure.The suggestion is that the front toe of the landslide should be improved as soon as possible.