库水位变动条件下土-水特征曲线对滑坡稳定性计算结果的影响研究

Research of SWCC on Stability Calculation of Landslides under Reservoir Water Fluctuation

库区滑坡的稳定性受库水涨落影响较大,为了分析库水位变动对滑坡稳定的影响,基于非饱和理论的有限元软件进行数值模拟,并需要用到非饱和土的相关参数,特别是土水特征曲线对滑坡稳定性的计算结果影响较大.文中一个实际算例采用不同土-水特征曲线时,计算所得结果相差较大,为了探究土-水特征曲线对滑坡影响的大小及原因,计算了当滑坡土体饱和含水量、饱和渗透系数相同时,3种典型土的土-水特征曲线所对应的稳定性系数,并得到以下结论:库水的升降作用对非饱和土质滑坡的稳定性有较大影响;由黏性土质滑坡的土体特性及计算说明表明:黏性土质滑坡在库水位变动作用下较粉土及砂土滑坡稳定,土-水特征曲线对考虑非饱和特性的滑坡安全系数影响较大,即同一含水率条件下基质吸力越大的土体滑坡的稳定性越好.

The stability of landslides is under the influence of reservoir water level fluctuation. Based on the finite element software of unsaturated theory for numerical simulation, and need to use the related parameters of unsaturated soil, especially for the soil-water characteristic curve（SWCC） which influence the stability of landslides. A practical example with different SWCCs if given, the calculated results are very different. In order to study the degree and reason of the landslide effect of the SWCC, calculated as the landslide soil satura- tion moisture content, saturated infiltration coefficient are the same, SWCCs of three kinds of typical soil corresponding to the stability factors, and some conclusion are obtaind as follows, the lifting effect of reservoir water level on unsaturated soil slope stability influence; the stability factor of the cohesive soil slope is larger than the silt, sandy soil slope when reservoir water level fluctuation; the SWCC has great influence on the stability of unsaturated soil slope; the matrix suction is larger, the soil landslide is more stable when the moisthre content is same.