Research On Deformation Prediction And Control Measures Of High-speed Rail Tunnel Shield Crossing Existing Traffic Line

Because high-speed railways(passenger dedicated lines)have the advantages of fast speed,comfort,economy,and high safety factors,they are the preferred mode of transportation for people.Therefore,high-speed railways are being constructed on a large scale,and new high-speed railways are mostly constructed by underground tunnels.For today’s society with well-developed transportation,tunnel construction is unavoidable to cross existing roads,which will affect the structural integrity of existing roads on the ground,and in severe cases will affect the safe operation of existing roads.Therefore,it is very necessary to study the settlement and deformation laws of the new high-speed railway tunnel caused by the shield crossing the existing traffic line and take corresponding effective control measures.This paper combines the engineering examples of the Wangjing Tunnel Shield on the Beijing-Shenyang Passenger Dedicated Line to pass through the existing roads(Capital Airport Expressway and Capital Metro Airport Line),and uses ANSYS finite element software to analyze and study the combination of simulation and actual site monitoring.The main research contents and conclusions are as follows:(1)ANSYS is used to establish the corresponding three-dimensional numerical model of the shield tunnel crossing the airport expressway and subway airport line.(2)The effects of different tunnel construction intervals,different shield machine earth bunker pressures,and different simultaneous grouting pressures in the tunnel on the settlement of the existing airport were simulated and analyzed.It is concluded that the larger the difference between the two tunnel construction intervals,the better the road surface settlement and settlement rate are controlled;the larger the parameters of the earth bunker pressure and the grouting pressure are,the smaller the settlement will be.(3)The monitoring scheme in construction is introduced in detail,and the data obtained from the on-site monitoring are analyzed.It is concluded that the settlements of the airport expressway and subway airport line are within the control indicators.(4)Through the setting of the test section,it is determined to take reinforcement measures when crossing the existing traffic line,and the airport high-speed and subway airport lines are respectively reinforced and simulated,and the comparison of the settlement of the airport highway pavement before and after reinforcement is analyzed;the different reinforcement methods are analyzed Comparison of the Subsidence of the Subway Airport Line.It is concluded that the settlement law before and after reinforcement is roughly the same,and the settlement is effectively controlled by grouting reinforcement.(5)Comparing the reinforcement simulation results of the airport high-speed and subway airport lines with the actual monitoring results on the site,the simulation prediction results are consistent with the actual construction measurement results,which verifies that the numerical simulation is useful for construction.