Abstract: In the light of special geological conditions of high rock slope in southwest China, we propose a new monitoring method which integrates the monitoring of slope surface, shallow-layer, deep-layer and microseismic monitoring based on long-term engineering practice and summary. According to monitoring results and the geological conditions and slope failure mode, we analyze the deformation of area with dense unloading fissures responding to slope excavation, and summarize the deformation characteristics and analyze its influence on slope stability. The area with dense unloading fissures on the right bank slope of Dagangshan hydropower station is taken as a case study. Furthermore, we compare the conventional monitoring results and microseismic monitoring results with the results of numerical simulation by RFPA^3D. The comparison reveals that the influence of dense unloading fissures is mainly reflected in the slope rock mass structure along the surface deformation.

Key words: Dagangshan Hydropower Station, slope monitoring, microseismic monitoring, dense unloading fissures, high-steep slope, stability analysis