三峡库区白家包滑坡变形机制分析

Analysis of Deformation Mechanism of Baijiabao Landslide in Three Gorges Reservoir Area

为研究三峡库区涉水滑坡的动态变形机理,以白家包滑坡为研究对象,依据地质勘查,降雨及库水位资料,运用专业监测数据与数值模拟相结合的分析方法,研究了滑坡的成因及变形机制.结果表明:滑坡变形呈阶跃式增长,4~9月份为主要变形期;各监测点自2006年起每隔3年累积位移有较大提升的"规律",分析认为是滑坡体应力场调整显示变形增大;库水位快速下降与滑坡地表位移增加有较好的相关性;且库水位波动与滑坡稳定性呈正相关变化.坡体的变形原因经分析为坡体外荷载卸荷及坡内指向坡外的动水压力;滑坡目前处于蠕滑变形阶段;若库水位快速下降与汛期强降雨共同作用,滑坡变形将进一步增大.

In order to study the dynamic deformation mechanism of the fording landslides in the Three Gorges Reservoir area, taking the Baijiabao landslide as the research object, and then based on the data of geological prospecting, rainfall and reservoir water level in recent years through the method of combining professional monitoring data with numerical simulation, the formation mechanism and the causes of Baijiabao landslide are analyzed. The result shows that the deformation mode is step-type-increase every year and from April to Sep- tember as the main deformation period. The reason for cumulative displacement of each monitoring point has been greatly increased every three years is that the stress field adjustment of the landslide leads to the deformation increasing since 2006. There is a good correlation between the rapid decline of reservoir water level and the increase of the cumulative displacement. The change of landslide stability has a positive correlation to the fluctuating reservoir water lever. By analysis, it is shown that the unloading of the slope external loads and seepage pressure from internal to outside are the main causes of the deformation of landslide. The landslide is currently in the stage of creep deformation. If the reservoir water level decreases rapidly and the heavy rainfall in flood season, the deformation of Baijiabao landslide will be further increased.