对某水电站扩建工程的古滑坡体，结合有限元法和 极限平衡法的各自优点，对其变形破坏机理及稳定性进行了综合研究。施工期的两次古滑坡 体局部变形失稳，验证了前期稳定性分析成果。另分别根据两次变形失稳的监测资料和变形 破坏机理，制定了压脚回填、加强排水等合理的治理方案，并在工程中得到了应用，确保了 施工期的坡体稳定。

For the old landslide of the expansion project of som e hydropower station, the deformation failure mechanism and stability of the slo pe were respectively studied through the finite element method and the ultimate equilibrium method, and the two times local sliding of the old landslide during excavation testified the results of previous stability analysis. Based on monito ring data analysis and mechanism investigation, some synthetically reasonable countermeasures, such as, filling slope toe and installing slope drainage etc., were taken in time, and safety in construction was guaranteed. The method of stability analysis and experience of engineering reinforcement of the old landslide can be useful for other similar slopes. 