降雨和库水位联合作用下库岸滑坡模型试验研究

受库区水位波动和降雨影响，库岸大量老滑坡体变形加剧，地质灾害问题十分突出。为研究库岸滑坡影响因素、变形演化规律及失稳条件，以大型物理模型试验为手段，选取三峡库区黄土坡滑坡临江Ⅰ号崩滑体为对象，通过考虑水位波动、降雨及其组合作用等诱发因素，开展了一系列的库岸滑坡模型试验研究。试验结果表明：水位升降，变形主要集中于模型坡体前缘，其中，水位抬升过程中，滑坡模型变形较小，变形加速阶段出现于水位下降期间，且变形速率与水位下降速率成正比，即临江Ⅰ号崩滑体为典型的动水压力型滑坡；降雨影响下坡体变形在时间和空间上存在明显分区现象，时间上，变形发展主要集中于坡体浅表层饱和之后，即短时降雨对坡体变形未产生显著影响，空间上，坡体前缘和后缘变形剧烈；库水位下降和强降雨联合作用下坡体前缘产生局部流滑破坏，并溯源发展至前缘整体破坏，为典型的牵引式破坏模式。试验揭示处于临滑阶段坡体，其孔隙水压力、土压力变化呈现异常频繁的波动现象，可为滑坡预警预报提供一定参考依据。

Experimental study on reservoir landslide under rainfall and water-level fluctuation

Due to rainfall and water-level fluctuation, deformation increases on a large number of landslides , which create severe geologic hazards problems in Three Gorges reservoir area. The study of influence factors, deformation evolution rules and instability conditions of reservoir bank landslide is conducted by physical modeling test. Taking Huangtupo riverside slump-mass No.I as an example, a typical reservoir landslide in the Three Gorges Reservoir area, , a series of model tests of landslide was carried out by taking into account the induced factors such as water level fluctuation, rainfall and their combination. Test results show that the deformation mainly locates at the front edge of the model slope during water level fluctuation. The deformation acceleration stage occurs during the decline of water level, and the deformation rate is directly proportional to the water level decline rate, while deformation is relatively small with rising water level. Therefore, the landslide of Huangtupo riverside slump-mass No.I is a dynamic-water-pressure type. The model deformation shows obvious spatial and temporal zoning under rainfall. The deformation mainly occurs when the shallow part of the model is saturated. Spatially, large deformation is generated at the front and trailing edge of the model slope. The model slope fails from local slip failure to the leading edge failure under heavy rainfall and decline of water level, showing a progressive retrogressive mode. Finally, the experiment reveals that abnormal fluctuations of pore water pressure and earth pressure occur at the near-sliding stage, which can provide some reference for landslide warning and prediction.