Force Performance Analysis And Construction Monitoring Of Auger Pile Retaining Structure In A Subway Station

Abstract:This paper is based on pit construction monitoring projects of Changsha subway station.In this paper, the Monitoring Data has been analyzed in detail.The finite element software Plaxis2D has been introduced in depth,and a numerical simulation has been applied to the practical engineering.The factors that may affect the pile horizontal displacement during excavation has been analyzed. The main research work are as follows:(1) Early at the station excavation, a survey on the surrounding environment has been conducted. Feasible monitoring measurement program has been developed in accordance with the requirements of the design and specification, and the monitoring project content has been determined, which included the pile deformation of the supporting structure, the surrounding surface subsidence, groundwater level, support axial loads. At the beginning of the station foundation pit excavation measuring point has been embedded. Monitoring during excavation. Monitoring data were processed, and reported to ensure the smooth progress of the foundation pit excavation and construction;(2) Pit pile top vertical displacement, the surrounding surface subsidence, deep horizontal displacement, steel support shaft power monitor measurement data in pit excavation in the south has been analyzed,which has been proved that the pit of this subway station was in a stable state during pit exvacation.(3) Introduced the basic theory of the finite element method, and using geotechnical finite element software Plaxis2D to simulate excavation process of D104measuring point, according to the standard sectional design parameters. Comparing the simulation result value and the actual value, we found there was a greater difference between the two;(4) Between simulated and measured values, there were six possible influencing factors; (5) Based on the original model, adding the factors affecting the simulation one by one, to analysis the variation of pile horizontal displacement curve in the different influencing factors;(6) Based on these six impact factors, debugging the parameters of the original model,which can obtain a correction model simulation results. Compared with the measured values, there have a better fit.