用有限元强度折减法求边坡稳定安全系数

Analysis on safety factor of slope by strength reduction FEM

利用有限单元法 ,通过强度折减来求边坡稳定安全系数。通过强度折减 ,使系统达到不稳定状态时 ,有限元计算将不收敛 ,此时的折减系数就是安全系数。安全系数的大小与所采用的屈服准则有关 ,本文对几种常用的屈服准则进行了比较 ,导出了各种准则互相代换的关系 ,并采用莫尔 -库仑等面积圆屈服准则代替莫尔 -库仑准则 。

An analysis on safety factor of slope through c-φ reduction algorithm by finite elements is presented. When the system reaches instability, the numerical non convergence occurs simultaneously. The safety factor is then obtained by c-φ reduction algorithm. The factor is related to the yield criterion. This paper presented a comparison of several yield criterions in common use and deduced the substitutive relationship of them. For convenience the Mohr Coulomb criterion is replaced by Mohr Coulomb equivalent area circle criterion, which was proposed by professor Xu Gancheng and Zheng Yingren in 1990. Through a series of case studies, the safety factor of FEM is fairly close to the result of traditional limit equilibrium method. The applicability of the proposed method was clearly exhibited.