| With large depth and length-width ratio, foundation pit of urban subway station was generally surrounded by dense buildings and underground pipers. The influence of deep excavation on surrounding environment should be controlled strictly. Based on two station foundation pits of No.2 subway in WuHan city, several indicator values and the variations of them were concluded under the initial design program. The results of the research could be used by other similar deep foundation pit projects for reference on design and construction.The simulation of dewatering of foundation pit of station JiangHan road by professional software PLAXIS and the comparison of results of total stress method, dewatering inside and outside the pit leads to some conclusions. Because of dewatering, the inner forces and displacements of supporting structure, ground settlement and its effect on surrounding environment increased greatly. Dewatering outside the pit causes more stability of supporting structure, but more influence on environment than dewatering inside. The effect of foundation pit by well depth depended on the permeability of soil above and below the end of the well.Large finite element software ABAQUS was used to analysis 2-D and 3-D simulation of foundation pit of station HongShan square. The research indicated: supporting structure got larger rigidity and stability when the cover and cut semi-inverse construction method was used. Ground settlement which was mostly caused by overloads had a large effect range and the maximum value almost happened at the centre of overloads. The displacements of foundation pit and the axial forces of braces got obvious space affect. As the distance to the corner of foundation pit decreased, the values and areas of every aspect of displacements were smaller.Finally, according to the analysis of numerical simulation results and combining with the requirements of relative code, some advices about the design and construction of foundation pit were given. |
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