High slope stability analysis of flood and sediment releasing tunnel outlet of Shenxigou Hydropower Station

The natural slope at outlet of flood and sediment releasing tunnel of Shenxigou Hydropower Station is high and steep,and the construction site is narrow with strong unloading,therefore,the structural layout of entrance sluice chamber is difficult.After the entrance slope was excavated,the slope foot support role was lost,resulting in difficulty of blasting.Through investigation of the geological condition,we analyzed its geological features and calculated stability index quantitatively to evaluate its stability.The structure of tunnel entrance chamber was optimized resulting in lower investment,construction period,and construction risk.