用有限元强度折减法分析非饱和土边坡稳定性

Unsaturated slope stability analysis of strength reduction fem

大多数天然和人工土坡都是非饱和土边坡,由于基质吸力的存在使得边坡的安全系数有所提高。基质吸力和边坡的稳定性密切相关,然而基质吸力的大小随着边坡的环境改变而改变。基于Mohor-Coulomb破坏准则和强度折减法,针对不同地下水位、边坡坡度和基质吸力相关的内摩擦角b,对非饱和土边坡稳定性进行了有限元计算。计算结果表明,采用无量纲位移Eδmax/rH2随强度折减系数变化的关系曲线上位移陡然增大时所对应的强度折减系数,作为边坡的稳定安全系数是合理的。

Most of natural and man-made slopes are unsaturated slope, and the matric suction makes the safety factor improved. There is a closed relationship between matric suction and safety factor of unsaturated slopes. But, matric suction is changeable with different external conditions. Based on strength reduction method, it analyzes stability of unsaturated slopes with different groundwater level and φ^b. The critical strength reduction factor is defined to the iump point in the curve relating the computed dimensionless displacement Eεmax/rH^2 to the strength reduction factor. The numerical results indicate that this criterion is reasonable.