OPTIMIZATION ANALYSIS OF REINFORCEMENT FOR LARGE-DIAMETER METRO SHIELD TUNNEL UNDERCROSSING THE EXISTING RAILWAY
The construction of large-diameter shield tunnel has a disturbing effect on the adjacent soil.Based on a metro section project,a three-dimensional numerical model including shield tunnel and railway structure is estab-lished.The displacement changing characteristic of railway tracks under different reinforcement schemes,reinforce-ment parameters,reinforcement lengths,and reinforcement ranges are studied.The results show that the track dis-placement does not meet the requirements under the non-reinforcement and single line reinforcement schemes,while the double line reinforcement scheme meets the requirements.The displacement of the track is approximately exponentially related to the elastic modulus of the added solid,but after exceeding a certain value,the degree of dis-placement improvement decreases.The longitudinal horizontal displacement,vertical displacement,and reinforce-ment length of the track are approximately exponentially related.Compared to the local reinforcement at the top,the vertical displacement of the track decreased by more than 55%after the reinforcement of the 3/4 section,and the dis-placement met the control standards.