降雨对均质各向异性土质边坡稳定性的影响

Effect of rainfall on stability of anisotropic soil slope

采用有限元法分析了非饱和均质各向异性土坡中的降雨渗透过程和土水相互作用的变化过程,使用修改的Mohr-Coulomb 破坏准则考虑非饱和土的抗剪强度,根据基质吸力变化引起抗破坏强度变化的原理,寻找最危险的滑移面位置.计算最小稳定安全系数,研究了土坡遭受降雨渗透时的安全稳定问题。实例分析结果表明,该法在评判降雨时非饱和土坡的稳定性方面是合理可行的。同时分析数据表明裂隙的存在对土质边坡稳定性的影响是显著的,在对雨水入渗的土边坡稳定性分析时,必须考虑裂隙的影响。

This paper presents a procedure for calculating the safety factor for an unsaturated and anisotropic slope suffering from rainfall infiltration.The process of infiltration into a slope due to rainfall and its effect on soil slope behavior were examined using a one-dimensional finite element flow deformation coupled analysis program.The modified Mohr-Coulomb failure criterion was adopted for unsaturated soil strength considering variations in strength due to the presence of matric suction.A safety factor was calculated based on the smoothed stress field obtained from finite element analysis;and an optimization technique was used to search for a critical slip surface.Some numerical examples are analyzed.The results illustrate a typical process of infiltration into unsaturated soil slopes and the effect of hydraulic conductivity on slope stability during reinfall-induced infiltration.And the analytical data indicate that the existence of the cranny has a distinct effect on anisotropic slope stability.The effect of cranny should be considered in analyzing stability of slope infiltrating by rainfall.