Mechanical and deformation characteristics of diaphragm wall system of Beijing metro station

Wangjing station of Beijing metro line No. 14 adopts the support system of underground diaphragm wall + steel support as well as diaphragm wall + steel support + anchor cable. The analysis of monitoring data shows that the influence range of excavation on the surrounding soil is close to the depth of foundation pit. The shapes of settling tank s of steel support section and mixed support section are different. The surface subsidence of mixed support section is larger than that of steel support section. In the mixed support section, when the excavation of foundation pit is shallow, the displacement of diaphragm wall is cantilever distributed. With the increase of excavation depth, the displacement is parabolic. The axial forces of first layer of steel strut are close to the work ones, and the tension of the lower anchor cable does not give full play. In the steel support section, the deformation of diaphragm wall presents rigid motion characteristics. The axial forces of steel support presenting stress relaxation and growing process have obvious effects of time and space. The axial forces of angle brace of steel support at shield well are quite gentle, the fluctuation is not large, and the spatial effects of structure are obvious. Two kinds of supporting system both can satisfy the requirements of deformation control indices of retaining structures.