大光包滑坡启动机制的物理模拟试验

Physical simulation on the formation mechanism of the Daguangbao landslide

安县大光包滑坡是汶川地震触发的规模最大的滑坡,为了研究其形成机制,本文结合野外现场调查,利用三维振动台物理模拟试验,研究了大光包滑坡在地震作用下的启动机制与破坏过程,探讨了滑坡发生与坡体结构的密切关系。研究结果表明:大光包滑坡一个楔型槽状滑落体,沿着白云岩沙化层面和坡体中垂直于层面倾坡内早期X构造裂隙构成,是层面与裂隙在地震力作用下扩展并破坏的宏观表现;振动作用下坡体首先在坡顶产生一系列的拉张裂缝,随后在坡体下部产生剪切裂缝;后缘拉裂面、东侧白云岩层面和西侧拉裂边界将坡体切割成楔形体并滑下;滑坡为一后退式滑坡,呈多次后退式破坏。

The Daguangbao landslide in Anxian County is the largest landslide occurred in the Wenchuan earthquake.In order to examine the formation mechanism of the landslide,based on field investigation,a 3-dimensional vibrostand physical simulation test is used to study the formation mechanism and destroy process and the affinity of the landslide and the slope structures is discussed.The results indicate that the landslide is a wedge and trough shaped fall,it formed by the underlying layer of sinianperiod dolomitite and early X tectonic fractures orthogonal to the layer.The landslide formed by the layer and crevice in the earthquake.Tension crevice appeared first on top of the slope,soon after shearing crack appeared on the bottom of the slope,the crevice formed in order.The pull cracks on top of the slope under vibrations,the slope slide face forms by the layer on the right of the slope,and tension crevice appear on the left of the slope.They form a wedge and trough shaped fall.The slope is a fallback one and it fell back repeatedly.