三峡库区重庆市奉节县花乐村滑坡成因机制及稳定性分析

THE FORMING CAUSE AND THE STABILITY ANALYZE OF THE LANDSLIDE IN HUALE VILLAGE,FENGJIE COUNTY,THE CITY OF CHONGQING

平皋乡花乐村滑坡位于奉节县平皋乡高店村 ,是在老滑坡体上多次复活的具有两级滑面的大型基岩滑坡 ,其前缘覆于长江一级支流———梅溪河之上 ,滑体长 1.1km ,宽 5 40m ,体积 1.188× 10 4m3 ,老滑坡体具多组剪切裂隙和风化裂隙 ,前缘受河水冲刷形成有效临空面 ,在较大孔隙水压力作用下形成。浅层滑体为块石土松散堆积物 ,滑移面为块石土与碎裂岩体的接触界面 ,目前处于正在贯通阶段。据岩土样品的试验值、现场大剪值 ,结合地区经验值及反算值 ,确定计算滑面稳定性及剩余滑坡推力的抗剪参数 ,考虑到未来三峡水库蓄水 ,在不同工况下对老、新滑坡体进行稳定性计算 ,结果表明老滑坡在各种条件下是稳定的 ,新滑坡在饱水及水库蓄水后 ,处于临界蠕滑或失稳状态 ,需尽快进行治理。

Huale Landslide is located in Huale Village, and is a large scale landslide with two sliding faces in an old landslide body. Its front part is near the Meixi River which is the tributary of Changjiang River. The old landslide body, whose length, width and volume are 1.1 km, 540 m and 1.188×10 4 m 3, has several groups shear cracks and weathering cracks. The landslide's front part has been being washed by the water so that an effective empty surface formed little by little. The epimetamorphic sliding body was formed by macadam. The sliding face is the contact face between the macadam and the fragment rock. According to the test data of rock sample, the data of site investigation, we can get the parameter of the landslide's stability and the anti-shearing parameter. Because of water in the reservoir Three Gorges, we calculate the result of the stability of the old landslide and the new landslide under the different conditions. The results show that the old landslide is stable in different conditions while the new landslide is in critical creeping motion when the landslide body is in water-saturation. Therefore, this landslide need to be controlled as soon as possible.