Quality control of right bank arch dam abutment excavation of Dagangshan Hydropower Station

Dagangshan Hydropower Station is a double-curvature dam that requires a high excavation quality on abutment.The replacement excavation is needed for partial foundation cushion of the abutment and the foundation surface are in 5 polyline type,causing difficulties of pre-splitting construction.Through comparison and selection,the construction scheme of excavation by bench blasting from top to bottom,ballast collecting by bulldozer and dumping into foundation pit by backhoe was adopted.The quality key points including over excavation and under excavation,flatness,residual pore ratio,particle vibration velocity were controlled strictly through emphasizing the process control,and the excavation quality reached an excellent level.