Stability Analysis Of Metro Tunnel Construction Of Lanzhou Rail Transit Line 2

Taking the underground tunnel of Lanzhou Metro line Line 2 as the engineering background,this paper uses the combination of theoretical analysis,numerical simulation and field monitoring to construct the shaft transition through the positive line tunnel in the process of underground excavation of Metro tunnel,The comparison of the construction scheme of the main line of the dark excavation tunnel and the excavation construction have carried on the thorough research to the engineering difficulty problem,such as the influence of the near existing building,and put forward the reasonable excavation construction plan and the reinforcement protection measure suggestion in the excavation section of the parking lot of the drainage South road of Lanzhou Metro line Line 2.The main work carried out in the paper and the main results achieved are as follows:(1)Based on the experience of similar projects,this paper analyzes the difficulties in the construction of shaft transverse through line during the construction of underground tunnel,and puts forward two construction schemes,"excavation transverse channel after permanent cover of Shaft" and "permanent cover construction of shaft after excavation of advanced transverse channel with Shaft".Through the comparison and selection of numerical simulation,the construction scheme of "permanent cover construction of shaft with advanced transverse channel after excavation of shaft is determined" in the underground excavation section of the parking lot of drainage South road of Lanzhou Metro line Line 2.The field monitoring results of tracking construction show that the construction scheme based on numerical simulation analysis is reasonable and feasible.(2)By means of numerical simulation,this paper optimizes and analyzes the excavation and construction scheme of the double-arch tunnel mine method in the Dark excavation section of the parking lot,probes into the stability of the stratum and structure in the construction process of the underground excavation tunnel,and based on the numerical simulation analysis,prejudge the safety hidden trouble which may appear in the construction process and puts forward the corresponding measures The on-site monitoring and analysis of the tracking construction proves the rationality and accuracy of the numerical analysis results.(3)This paper summarizes the adverse effects of the dark excavation tunnel on the existing buildings on the surface during the construction process,analyzes the key problems in the construction of the dangerous buildings interval of the underground excavation side of the parking lot of the flood crossing road,and preliminarily determines the construction scheme of the underground excavation and the dangerous buildings reinforcement scheme.Through numerical simulation,This paper studies the construction stability of the dangerous buildings interval of the tunnel side through the entrance line of the parking lot of flood South Road,and analyzes the effectiveness of the dangerous buildings reinforcement measures in combination with the field monitoring data.The results show that the isolation pile can effectively control the deformation of the building through stress isolation,so as to ensure the safe use of the building.