非饱和渗流对滑坡稳定性的影响研究

Study of influence of unsaturated seepage on stability of landslide

库水位下降对滑坡的稳定性具有较大影响。提出了土水特征曲线的多项式约束优化模型和一种新的溢出面边界条件约束函数,并用ANSYS的APDL语言编制了饱和-非饱和渗流程序。以赵树岭滑坡为例,首先利用核磁共振(NMR)技术和钻孔资料建立该滑坡的物理模型,然后模拟了长江水位以不同速度从175m下降到145m时该滑坡的渗流场,对每种工况不同时刻的滑坡稳定性进行了计算。实例分析结果表明,库水位下降过程中稳定性系数会出现极小值,库水位下降速度越大,稳定性系数极小值越小,出现极小值的时刻也越早。

The stability of landslide is affected by the drawdown of reservoir water level. A polynomial constrained optimized model for soil-water characteristic curve and a new restrict function for overflow surface are put forward. Based on these, a saturated-unsaturated seepage program is edited with APDL in ANSYS. Zhaoshuling Landslide is taken as an example, firstly the physical model is established through Nuclear Magnetic Resonance and bore data, and then the seepage fields are simulated when the Yangtze River water level falls from 175 m to 145 m at different speeds, the stability of the landslide at different times is also analyzed. The result shows that the bigger the fall speed is, the least the minimum value of the stability coefficient is, and the earlier the value comes.