The Application Research Of Between Zhengzhou Xinzheng Inter-city Railway Tunnel Deep Foundation Pit Supporting

Along with the deepening of the urbanization process, more and more traffic hub synthesis is constructed and utilized. especially for the center with large airport hub, it combines air, ordinary roads, railways, highways, urban subway traffic elements. At the same time in the limited space for the construction of the infrastructure is a very thorny problem, it is easy to produce interference. The research object of Zhengzhou-Xinzheng rail tunnel deep foundation pit adjacent pile foundation, in the process of excavation, the inevitable exist between influence each other. On the one hand, the excavation of foundation pit soil happen to pit the movement of the existence of the pile foundation hindered the pile move and make the soil produce additional earth pressure, when additional earth pressure exceeds the withstanding capability of the pile foundation, pile foundation damage occurs and cause the damage of the upper structure. On the other hand, the existence of the adjacent pile foundation also affect excavation, scholars have made relatively few studies on this issue, research results are rare.In this paper, on the basis of summarizing the predecessors’ research, combined with specific engineering, using the principle is the deep foundation pit supporting structure design software and finite element analysis software ABAQUS, the adjacent pile foundation of Zhengzhou-Xinzheng rail tunnel deep foundation pit supporting engineering are studied, at the same time also on adjacent pile foundation pile condition change on the influence law of foundation pit supporting structure made a tentative study, and put forward the relevant conclusions.(1) Field monitoring deformation of pile and soil settlement pit weeks are much smaller than the principle is calculation result of deep foundation pit supporting structure design software, to produce the results the reasonable explanation is that the adjacent pile foundation has beneficial effects on foundation pit excavation.(2) Both with and without pile pile foundation pit in both cases the finite element simulation results prove the existence of adjacent pile foundation has beneficial effects on foundation pit supporting structure indeed. After a carefulanalysis of the cloud that adjacent pile foundation after the supporting structure of the soil as the soil skeleton constraint move, for share most of the earth pressure of retaining structure.(3) Other pile fixed when the condition of the optimal pile length with the length of the deep foundation pit supporting structure is quite; Optimal pile diameter and optimal stiffness is to make the soil pile to resist the mobile without produce large deformation when the pile diameter and stiffness; Best pile and the closer the distance between the supporting structure in theory, the better, but to ensure the safety of adjacent pile foundation itself and the supporting structure construction convenience.(4) Pile condition changes sensitive factor to the beneficial effects of foundation pit excavation for pile stiffness and the distance between the pile and retaining structure, adjustment of the two factors bring the beneficial effects of relatively more significant effect.