Effect Of The Building In Layered Excavation Deep Foundation Pit

With the development of urban construction and reconstruction, the project of foundation pit goes into lager scale and depth. Meanwhile, it is generally surrounded by dense buildings. The working space is very narrow and there are always some permanent construction and public service which must be protected. Therefore, there is a high requirement of the stability of foundation pit and the control of displacement, especially when it is close to the foundation of some construction. It is rather difficult to meet the need of protecting the surrounding construction under the project design of foundation pit and it has to deform in most cases. Although, many scholars have already studied a lot in the control of the foundation pit deformation, there still remains many questions need to solve in seeking the relation and rule among the deformation of foundation pit bracing, stratum and buildings around the foundation pit.In order to find out the deformation rules of construction and bracing structure in the process of foundation pit excavation, this dissertation studies the foundation pit, bracing structure and construction systematically with analysis software ANSYS. In the dissertation, we employ the numerical simulation to certain stratum. First, we study the situation without construction in simulation, and we analyze the deformation of foundation pit under both the circumstances without bracing and with cantilever pile using the construct way of layered excavation. We also compare the difference between the two circumstances. Second, we simulate the horizontal displacement and the settlement of the surrounding buildings under the different circumstances in which the distance between constructions and foundation pit differs and we use four different bracing formations: cantilever pile bracing only; cantilever pile bracing with one layer of anchor poles; cantilever pile bracing with two layers of anchor poles and cantilever pile bracing with three layers of anchor poles. Then, we conclude the changing rules in the process of layered excavation under the four different circumstances. Finally, we get some conclusions which are valuable for design and construction of foundation pit.