Stability assessment of a high rock slope by strength reduction finite element method

The dam site of Jinping-I hydropower station is located on the Yalong River and has complicated geological conditions. A steep rock slope with a height of about 530 m will be built after excavation of the arch dam abutment. There exists a huge wedge failure block in the left abutment slope which has a vital influence on the construction schedule and safety of the whole project. To evaluate the stability of the slope during construction, the strength reduction finite element method (SRFEM) is employed to simulate progressive failure of the huge block. The criteria for judging the failure of slopes are discussed for the SRFEM. The results from the proposed SRFEM indicate that excavation of the spandrel groove slope below an elevation of 1,885 m would drastically deteriorate the stability of the huge block. The implementation of shear-resistance tunnels effectively increases the safety factor of the huge block and ensures the stability of the left abutment slope.