水位变化引起分层边坡滑坡的实验研究

通过对分层的边坡在水位变化时滑坡的模拟实验，起的滑坡，重点考察了水位涨落速度对坡体稳定的影响，考察了分层坡体的滑坡模式、坡体变形、破坏和渗流引以及坡面从产生张拉裂缝直到形成滑面的整个过程，并对这类滑坡中的现象给出了定性解释。最后用有限元对实验坡体进行了应力和位移的静力场分析，计算结果与实验结果基本一致。

TESTING STUDY ON LANDSLIDE OF LAYERED SLOPE INDUCED BY FLUCTUATION OF WATER LEVEL

The frequent fluctuation of water level of Yangtse river will greatly influence the stability of the widely existing slopes in the Three Gorges reservoir zone,especially those layered ones. Apart from the fluctuating speed of water level,the behavior variation of geological materials will also play important roles in the failure of slopes. A new experimental setup was designed to study the behavior of a layered slope under the fluctuation of water level. The landslide pattern of a layered slope induced by fluctuation of water level is explored by means of simulating experiments. The influence of fluctuating speed of water level on the stability of layered slope is probed,especially the whole process of deformation and development of the landslide with time. The experimental results show that the slope is stable during the rising of water level,and the sliding body occurs in the upper layer of the slope under certain drawdown speed of water level. In the process of slope failure,some new small sliding body would be developed on the main sliding body,which would speedup the disassembly of the whole slope. A qualitative analysis and explanation about the phenomena occurring in such a kind of landslide are also given. As the permeability of the upper soil is very low,the gradient of out-seepage force of the pore water is very large nearing the crest of the slope. The large gradient of out-seepage force of pore water does cause the tensile cracks on the slope. Of course,the component of weight along the inclination is another unneglectable factor for the occurrence of this landslide. Furthermore,the softening effect of water on soil should be considered for a real landslide,especially for the initially non-saturated slopes. At last,the distribution of stress and displacement of the slope is calculated by using static finite element method,and the computation result is in good agreement with experimental result.