Effects of Pit Excavation on an Existing Subway Station and Preventive Measures

摘要

As traffic lifelines of modern cities, subways are being rapidly developed in China. With this development, an increasing number of subway interchange stations will be built at deep soft soil areas. Because of the absence of data on the effects of pit construction on existing subway stations, no theory is available to predict deformation of a subway station caused by adjacent pit construction. The proposed Line 10 subway station intersects with the operating Line 4 subway station at Hailun Road, Shanghai, China, where the underlying stratum is composed of several different sandy-silt layers and two confined aquifers. The double-layered confined water meets at the south end well of the proposed subway station. With such complicated hydrogeological conditions, the development of technology that can control the effects of groundwater and guarantee the safe operation of Line 4 during pit construction is essential. In this article, the effects of dewatering and pit excavation on the Line 4 subway station are analyzed through theory and finite-element simulation. A measure of groundwater treatment and a protection scheme for the subway station are proposed based on the analysis results, and a scheme optimization to successfully control the effects of pit construction is carried out. The research results of this article provide references and guidelines for similar projects in the future.