Abstract: A suspended watertight curtain pit with deeper submersible aquifer is presented as a case history. Throughout the establishment of theoretical formula analysis and finite element verification, the effect of excavation descending on the head at the depth of the maximum water level drop outside the pit, and analyze the change rule of the embedding depth of water stop curtain on the head at the depth of the maximum water level drop outside the excavation under the different ratios of the pit radius and the submersible aquifer. The head at the depth of maximum water level drops outside the pit after the excavation dewatering is obtained by equating the pit to a large dewatering well and bringing the formula for the influx of water in the pit into the formula for the pumping capacity of a single well of a pumping well. With the increasing ratio of pit radius and submerged aquifer thickness, the water-stopping efficiency of the suspended watertight curtain is first strengthened and then weakened until it stabilizes. In the ratio of pit radius and submerged aquifer is about 0.7, the watertight curtain water-stopping efficiency reaches its maximum. The theoretical formula estimation results in the pit radius and submersible aquifer thickness ratio of 0.7~1.6 and the finite element analysis results are closer, and in its ratio of 1.3 when the results are basically consistent. Under the ratio of pit radius and submerged aquifer thickness, the change rule of water stopping energy efficiency is the same in the theoretical formula and the finite element analysis results, while the finite element analysis results are slightly larger. By correcting the minimum seepage path the corrected results are closer to the finite element analysis than the original theoretical formulate.

Key words: Watertight Curtain, Finite Element, Deep Excavation, Dewatering Wells, Maximum Water Level Drop Depth