ANALYSIS OF KEY FACTORS AFFECTING THE COMBINED SUPPORT SYSTEM OF DIAPHRAGM WALL AND INNER SUPPORT IN HIGH WATER LEVEL SOFT SOIL AREA

A deep foundation pit of a subway in Tianjin is located in the center of the city. There are residential quarters, high-rise residential buildings, schools, research institutes and so on. The foundation pit is about 17.72m deep. The excavation area is large. The depth of foundation pit is deep. The groundwater level is high, and the soil layer is mainly composed of soft clay, such as silty clay. The foundation pit enclosure structure adopts the joint support type of underground continuous wall and inner support. In this paper, the characteristics of the stress and deformation of the continuous wall of underground continuous wall and the law of the surrounding ground settlement are studied by the control variable method. The law of settlement and deformation of underground continuous wall and surrounding surface is obtained, so as to determine the optimal supporting scheme of retaining structure. The research results can provide reference for similar foundation pit design.