Abstract:  To find the solutions of groundwater prevention and control in deep foundation pit excavation with shallow bedrock and quicksand strata facing river on three sides, the characters and stratum parameters of foundation pit project in Hefei Qingsanchong storage pond are analyzed. A set of comprehensive groundwater prevention and control measures, i.e., appropriate slope depth in upper part, blocking water around the foundation pit and inserting piles to the top of bedrock is put forward. Meanwhile, key technical points, i.e., the use of deep mixing pile and highpressure jet grouting pile in rocksocketed construction, the use of steel plate wall after bored piles crossing quicksand stratum, etc., are demonstrated. The implementation effect and monitoring data show that the impact of dewatering excavation on surrounding environment and supporting structure is within a reasonable range, and there is no obvious leakage on the side wall of the foundation pit, which proves that the overall effect of groundwater prevention and control measures is good.

Key words:

facing river on three sides, shallow bedrock, quicksand formation, deep foundation pit, sloping excavation, comprehensive prevention and control of groundwater