| Dewatering is generally adopted in the excavation engineering as a kind of groundwater control method, provides the convenience. At the same time, dewatering bring some of the environmental disaster, including serious ground subsidence and the buildings craze, roads and cracks of underground pipeline rupture caused by the ground subsidence.Firstly, ground subsidence happened at home and abroad, the research situation of dewatering and landsubsidence are summarized briefly introduced. Seepage models and consolidation theory are summarized. Put forward the research content and research route. Reviews the concept, hydrological and geological terms of seepage theory and its relevant boundary conditions and the initial conditions were summarized.Secondly, relyded on dewatering of Beijing subway line Yizuang line, water pumping tests are implied on confined water and free water according related technical specifications.Relevant data are gotton, and hydrogeologic parameters are calculated based on these data.Thirdly, K.Terzaghi consolidation theory and Biot consolidation theory was summarized, analyzed respectively applicable conditions. Seepage models and soil deformation models are researched.The subsidence of two step calculation model, the coupling model and the coupling model are summarized.The results of Analyses on landsubsidence of forming mechanism as follows: Effective stress is transformed by the water pore pressure gradually, so ground subsidence occurred to the corresponding level lags. And the influence various factors of ground subsidence are analysied, including the structure and soil layers, consolidation, and duration of pumping and drop.Finally, Ciqu south station’s soil layers are generalized, ground subsidence is canculated in theory method, monitoring data at pretent verify the practicability of the theory compared to the data caulated by theory method. Several engineering measures are come up with to reduce landsubsidence caused by dewatering. |
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