Study on the Impact of Sharp Turning Shield Tunnel Crossing Near the Existing Bridge
In order to explore the influence of large curvature shield tunnel on adjacent bridges in the process of sharp turn,a sharp turn tunnel crossing bridge project in Shanghai is taken as the background.Based on Midas numerical simulation software,a three-dimensional numerical model of sharp turn tunnel crossing bridge is established to study the influence of sharp turn tunnel on bridge pile foundation.In addition,combined with the on-site construction scheme,the controlling effect of stratum reinforcement measures on reducing bridge settlement and deformation is analyzed.The main conclusions are as follows:(1)affected by the shield tunnel crossing the existing bridge,the width of the surface settlement trough is 3.44D(D is the diameter of the tunnel).When the shield passes through the bridge,the disturbance to the stratum is the largest,and the cumulative maximum settlement of the surface accounts for 90%of the maximum settlement.(2)In the process of shield approaching the existing bridge,the pile deformation is mainly Y-direction(longitudinal)deformation.When the shield crosses the bridge,the tilt deformation of the pile is the largest.(3)After using MJS to reinforce the excavated soil,the surface settlement and the horizontal displacement of the bridge pile foundation are sharply reduced.According to the numerical simulation results,the settlement deformation of the bridge is reduced by 38%,and the floating amount of the tunnel is reduced by 79.5%.
sharp turning tunnelexisting bridgenear-through constructionfinite element simulationdeformation control
NETL
NSTL
万方数据
