Numerical Analysis of Deep Foundation Pit Excavation Process

Abstract

Based on the background of a subway project to be built in a certain city, finite element analysis software Abaqus 6.1.4 was used to simulate and analyze the displacement changes of deep foundation pit excavation, underground diaphragm wall, steel support and other supporting structures. The results show that the maximum horizontal displacement of the diaphragm wall and the vertical displacement (settlement) of soil around the foundation pit occur at the midpoint of the long side of the foundation pit. The maximum horizontal displacement of the underground diaphragm wall reaches 13.9 mm, and the maximum horizontal displacement occurs 16m from the top of the wall. The maximum vertical displacement (settlement) of soil around the foundation pit is 9.5 mm and occurs 8m away from the edge of the foundation pit. For the deep foundation pit with large length and width, the deformation of the middle point and the end section of the long side of the underground diaphragm wall is relatively large compared with other positions, so a reasonable alarm value should be set separately. The axial force of steel support on the excavation layer will increase significantly, which is a focus of close attention in design and construction. The above results can provide some reference for the design and research of deep foundation pit excavation support in soft soil area.