Study On Dewatering Of Anchorage Foundation Pit Of Dongting Lake Bridge

Along with the establishment of the high-rise buildings and the application of underground space, the deep foundation pit engineering was born. There often exists groundwater in the construction process of deep foundation pit engineering, and the groundwater will have a serious impact on the safety of deep foundation pit engineering. Therefore, it is necessary to take a reasonable dewatering method before the excavation of deep foundation pit.Taking the foundation project case of Dongting Lake bridge as an example, this paper adopts indoor variable head test to determinate the permeability Coefficient of foundation pit, uses the theoretical analysis method to introduce the commonly used dewatering method of foundation pit and foundation pit dewatering scheme of this project, and takes advantage of the three-dimensional finite element software Midas GTS to simulate construction process of foundation pit dewatering and direct excavation respectively, finally compares and analyzes the characteristics of force and deformation about asymmetric gourd shaped underground continuous wall in two cases, and changes wall thickness respectively to establish 3D model according to the former two anchorage foundation pit on the model, studies the impact of wall thickness to itself stress and deformation.(1) Though consulting and studying the massive literatures, describe the present situation of foundation pit precipitation method and underground continuous wall.(2) With the use of indoor variable head test to determinate the permeability Coefficient of foundation pit. This paper determines the soil permeability coefficient under the condition of different void ratio and water content, and analyzes the influence of two factors on soil permeability coefficient.(3)To introduce the commonly used methods of foundation pit dewatering and the foundation pit dewatering scheme used in this project.(4)In combination with practical engineering, the 3D anchorage foundation pit model can be established by using the finite element software Midas GTS considering two kinds of situations of precipitation and no precipitation to simulate the process of foundation pit excavation, and obtain the influence of foundation pit precipitation to the stress and deformation of underground continuous wall supporting system; And on the basis above, simulate the force and deformation characteristics of different wall thickness, and get the conclusion that wall thickness can prevent the wall deformation in a certain range.