平面应变条件下两类有限元边坡稳定分析方法比较研究

对有限元边坡稳定分析方法中滑面应力分析法和强度折减法的安全系数定义进行了探讨,指出这两类方法的安全系数定义都是从强度折减的概念出发,与极限平衡方法中的安全系数定义概念上是一致的.在算例对比分析中,基于非关联流动法则,采用与经典摩尔-库仑准则相匹配的等效D-P准则,在平面应变条件下,对天然边坡(均质边坡、有下卧软弱层、有软弱夹层带)的稳定性进行了对比研究,并同传统极限平衡方法进行了比较.研究表明,两类有限元方法得到的安全系数大小以及相应滑动面形状和位置均十分接近,滑面应力分析法不适于计算失稳边坡的安全系数.

Comparison of two kinds of finite element methods for slope stability analysis under plane strain condition

The two kinds of definitions of safety factor in slope stability analysis by FEM(finite element method) were discussed,and it was indicated that the two definitions,which were based on the conception of strength reduction,were consistent with the definition in limit equilibrium method.In the analysis of examples,D-P yield criterion which is transformed from and matches precisely M-C criterion is used to analyze the stability of natural slope(homogeneous slope,undrained clay slope with a weak foundation layer,undrained clay slope with a foundation layer including a thin weak layer) under the plane strain condition.The results show that the shapes of critical slip surface and the magnitude of safety factor are very similar with those obtained by the two kinds of methods.It is also pointed out that the slip surface stress analysis method does not suit with calculating the safety factor of the instability slope.