Analysis On The Influence Of The Pile Foundation In The Construction Of Shield Tunnel Obliquely Acrossing The Structures

With the network of urban overground traffic from sparse to dense,and the increasing number of high-rise and super high-rise buildings,metro shield tunnel will inevitably pass through the pile foundation of buildings in the process of construction,which has an impact on the safety of buildings.This paper based on the engineering of the Shijiazhuang Metro line 3 from Shizhuang station to Shierzhong station,which will pass through the pile foundation of Heping West Road Viaduct,by using the finite element analysis software of tunnel modeling to build a 3D model before the construction beginning,and to analyze the impact of the construction process on the pile foundation of the viaduct,so as to provide a reference for the later constructing.The main contents and results are as follows:(1)Summarizing the research status of pile foundation and stratum in the construction of metro shield tunnel.(2)Through the 3D model built by the finite element analysis software,simulating the construction condition of the metro shield tunnel passing through the Viaduct Pile Foundation,analyzing the Viaduct Pile Foundation and the surface around the pier,and concludes that:(1)The relationship between the maximum deformation position of the pile body and the distance between the pile foundation and the tunnel presents an opening upward parabola.The closer the pile foundation on both sides of the tunnel is to the tunnel,the closer the maximum deformation position of the pile body is to the depth of the tunnel,the farther the distance from the tunnel is,the closer the maximum deformation position of the pile body is to the top of the piles;(2)the maximum settlement point of the ground is located above the center line of the right line tunnel,with the size of 5.8mm.The maximum ground settlement value around the pier is 1.7mm,The horizontal ground settlement curve presents a shape of "W",the pile foundation can reduce the ground deformation caused by the construction of shield tunnel.The maximum deviation value of the pile in the x-axis direction is 1.6mm,the maximum deviation value of the pile in the y-axis direction is 4.9mm,and the maximum deviation value of the pile foundation in the vertical direction is 3.1mm.These simulated values are less than the standard values,which shows that the construction parameters of the 3D model are reasonable,and the construction of the shield tunnel has little impact on the existing viaduct,which can provide reference for the subsequent construction.(3)According to the collected monitoring data of shield tunnel passing through the pile foundation of viaduct,the monitoring data of viaduct's piers and the surface around viaduct are analyzed.The results show that: According to the measured data,the maximum ground settlement value on the central axis of the piers is located above the centerline of tunnels,the settlement value of the right line is-5.36 mm,and the numerical simulation result is-5.8mm;the settlement value of the left line is-5.1mm,and the numerical simulation result is-4.9mm;the maximum ground settlement value around the 2# pier is 1.34 mm,and the numerical simulation result is 1.7mm;the maximum vertical settlement value of the 2# piers is-3.71 mm,and the numerical simulation result is-3.1mm.It shows that the difference between the measured data and the numerical simulation results is small,the construction of shield tunnels has little impact on the existing viaduct,and does not affect the safe and normal useing of the viaduct in the construction process.