Abstract: Bands of clefts appeared on the top of the water-entrance hole at a southwestern hydropower station during the excavation attracted lots of attention. Based on in situ investigation, the authors characterized the failure mode and simulate the excavation process using the FLAC~(3D). The results of calculation indicate the displacement of the slope and verify the development of the bands of clefts. The model also predicted the distribution of displacements within the slope after reinforcement. The results indicate that the maximum displacement in X direction amounts up to 5.4cm. With the effective anchoring reinforcement the slope reaches its stability by adjusting the stress and strain.