通过对边坡非线性有限元模型进行强度折减，使边坡达到不稳定状态时，非线性有限元静力计算将不收敛，此时的折减系数就是稳定安全系数，同时可得到边坡破坏时的滑动面。传统条分法无法获得岩质边坡的滑动面与稳定安全系数。该方法开创了求岩质边坡滑动面与稳定安全系数的先例。文章对此法的计算精度以及影响因素进行了分析。算例表明采用摩尔-库仑等面积圆屈服准则求得的稳定安全系数与简化Bishop法的误差为3%～8%，与Spencer法的误差为1%～4%，证实了其实用于工程的可行性。

An analysis method for slope safety factor through c - cp 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 - ψ reduction algorithm. The same time, the critical failure surface is found automatically. The traditional limit equilibrium method can't get the safety factor and failure surface of jointed rock slope. Strength Reduction FEM (SRFEM) presents a powerful alternative approach for slope stability analysis, especially to jointed rock slope. This paper analyzes the precision and error caused by different soil yield criterions、FEM itself、slope height、slope angle´cohesion and friction angle thoroughly. Through a series of case studies, the results show average error of safety factor between Strength Reduction FEM and traditional limit equilibrium method (Bishop simplified method) is 3 %～8 %，the error between SRFEM and Spencer's method is 1 %～4 % . The applicability of the proposed method was clearly exhibited.