Study On The Ground Settlement Induced By The Precipitation Construction In Soft Soil Foundation Pit

With the rapid development of China’s society and economy, the groundtransportation becomes more and more crowded. Therefore, it is necessary to developthe subway so that it can relief the pressure of the ground transportation. The economyin the southeast of China is active. In these regions, a number of subway excavation hasbeen constructed. However, there are a lot of soft soil layers in these regions. As weknow, the level of groundwater of the soft soil is shallow and the strength is low, so it iseasy to be deformed when excavation. In the soft soil foundation engineering, thechange of groundwater has a great influence on the deformation of the foundation. So ithas become an important and difficult study for precipitation pit design and constructionmethods in soft soil areas.Firstly, combined with the problems in the excavation and construction of the softsoil at the moment and on the basis of the single-well precipitation theory, the thesis setup2D and3D calculation models considering single-well pumping. The thesissummarized the developments and changes of the pore water pressure, the precipitationdepth and the ground settlement after the end of the pumping process and pumping.Secondly, the thesis set up a2D model considering deep foundation pit and precipitationconstruction on the basis of the practical engineering. Compared the model results withthe example results, the correctness of model is verified. Then, because the basisparameters of soil and construction step is approximate between Fuming Road Stationand Shanghai subway station, the model established in the thesis is used in the FumingRoad Station. The results show: deep foundation pit and precipitation construction mayintricate the change of the pore water pressure, the displacement of the soil behind thewall and the uplift of the soil in the deep foundation pit in the soft soil. And in the end,on the basis of the analysis in the chapter III, the thesis analyses the influence of the softsoil parameters and waterproof curtain.On the basis of the results in this study, it is benefit to develop the design theoryand method of deep foundation pit and precipitation construction and it has a greatguidance for the construction in the future.