关键词: 地面沉降、塌陷, 疏干排水, 减压井, 按需降水

Abstract: The dewatering design in the deep excavations in the urban area has an important role of minimizing the disturbance of the adjacent environment. To achieve this goal, the dewatering design should be based on the different underground soil conditions. For shallow groundwater depositions, the conventional method is to prevent the infiltration of surface water and to drain the shallow water tables. The well points are usually used to control the deep pressurized aquifers. Monitoring is an important measure in the ground surface deformation induced by the dewatering operation. The design requirements at every aspects of each element: installation of the borehole, casing lowering, filling of the filtering material, well washing and preliminary dewatering testing as well as dewatering operation, should be closely followed.

Key words: Land subsidence collapses , Underground drainage, Relief well, Dewatering