Monitoring analysis of internal forces and deformation of the retaining structure for deep subway station foundation pit in silty sand

In this paper the horizontal displacements of diaphragm wall, axial forces of steel struts and surface settlements for different stages in different zones are compared by analyzing the monitoring data of a deep subway station foundation pit support structure in Hangzhou. The results shows that the rate of deformation of the diaphragm wall increases during the excavation near the bottom of the foundation pit and the prompt pouring of the concrete of the bottom plate can prevent the kicking failure. The installation and the removal of a strut can cause the abrupt changes of the axial forces of its adjacent struts. The corner brace is easier to stable than the symmetrical one due to mutual restriction of the diaphragm wall. The water has a significant influence on the deformation of the foundation pit. The rate of the settlement near the foundation pit increases obviously during the rain. The foundation pit has obvious spatial effect and precise three-dimensional analysis is necessary for the improvement of the design accuracy.