Experimental Research on the Dewatering of Closed Excavation with Retaining Structure-Underground Diaphragm Wall

Based on a closed deep excavation with retaining structure-underground diaphragm wall engineering, and through pumping test and by the method of thesis, the hydraulic parameters of deep confined aquifer were acquired and the dewatering test was designed. The water sealing effect and the feasible of dewatering program were testified through the pre-dewatering test. The results of the pre-dewatering test indicated that the water lever of mixed wells outside the excavation and confined wells changes rather small and the water sealing effect works well during the 12 h dewatering process; the observation wells which are evenly distributed in excavation can satisfy the demand of underground water lever in the process of soil excavation. Therefore, it is indispensable, for large deep excavation with retaining structure-underground diaphragm wall engineering, to conduct pre-dewatering before dewatering process in excavation. On the one hand, the pre-dewatering test can testify the water sealing effect of underground diaphragm, on the other hand,it can provide data for the optimal designing of dewatering program.