Cross River Shield Tunnel Segment Structure Mechanical Response And Construction Control Technology Research

In recent years,the pace of infrastructure construction in China is accelerating,the tunnel shield construction more and more construction projects,especially the underwater tunnel project.However,the segment structure often appear to floating,faulting,cracking phenomenon in the process of shield tunnel construction.This paper is based on the domestic and foreign relevant research on the current situation and take the Xiangjiang tunnel project of Hejiang in Hengyang as the background,analysis of the shield construction stage modeling using MIDAS-GTS NX software,research on the mechanical response law of segment lining structure under construction load.(1)Modeling by MIDAS-GTS NX software,the mechanical response of segment lining structure of construction loads.With the increase of grouting pressure,horizontal and vertical displacement of lining segments were increased.With the increase of thrust force,horizontal and vertical displacement of the segment will be increased,but not obvious.Segment lining vault and arch bottom extrusion deformation of large arch waist,there is a corresponding level of compressive deformation;the maximum compressive stress is located at the middle of the arch.(2)This paper analyzes the mechanism of segment structure of floating phenomenon,by monitoring the data summarized segment floating Law: with the time increasing,the slurry viscosity resistance increases,the floating rate is gradually reduced;most of the displacement of the lining ring rises at the initial setting time of the grout;for a period of time after the initial setting,the floating value is smaller,and the final floating volume tends to be stable.(3)The segment structure fault mechanism analysis,summarizes the segment structure of the dislocation caused by factors,a formula is derived to calculate the dislocation of a single segment in the grouting process.Single segment dislocation equation showed that the grouting pressure is greater,the greater the amount ofsingle segment dislocation;the bolt bending segment stiffness,small fault Taiwan.The gap between the bolt and the bolt hole is large,the corresponding occurrence of segment dislocation is bigger.Therefore,it is of great practical significance to determine the magnitude of the wrong platform in advance to control the blocking of the segment.