The Structural Safety And Stability Analysis On Water-conveyance Tunnel In Crossing Overpass Urban Rail Transit

Conducting the study and analysis on the safety and stability of the rail traffic structure through the water conveyance tunnel shield is of great significance. Beijing Eastern main canal project is a cores component of the South-to-North Water Transfer Project,which is mainly arranged in the Northern and Eastern fifth-loop with a total length of44.7km. The body engineering is a reinforced concrete tunnel with a diameter of 4.6m(two-layer lining structure), while the East channel tunnel is constructed through shield method. Due 8 opened rail transit line are run through by Shield tunnel, there are a great difficulty and security risk in project implementation, thus, the way to reduce the influence of rail transit construction has become the key factor for the success of this project and the right choice of rail transport infrastructure protection program has become the key technology of engineering design.The main contents are as follows:(1)This paper sets Beijing Railway Line M15, which is the eastern main canal shield construe, as a typical case, analyzes the environmental conditions of East Canal through the M15 subway line, checks the structure of the M15, identifies the location relationship between two projects, explores and evaluates the geological condition crossing the area, and collects the underlying data for the safety analysis.Using ANSYS software, based on dig process of shield frame machine and the construction order, to simulate new East channel shield frame interval, simulate normal construction workers condition and the deformation value of double direction of cross and vertical under work condition of strictly controlling construction parameter for track traffic structure, propose deformation analysis on existence structure, discus overall security of M15 shield frame interval, while integrating the needed lane security, further proposing protection measures and deformation control standard for new East channel tunnel on shield frame structure. By comparing analysis and related standard requirements, the construction of East Canal crossing the M15 subway line tunnel with shield machine not hole-assisted measures and strictly controlling shield tunnel construction parameters of shield construction of the construction programmer are determined.(2) According to shield tunnel and rail transit positional relationship, riskclassification, structure, past work experience and comprehensive test section before crossing obtain construction parameters, the control method of East main channel tunnel holing line M15 is proposed, including: soil pressure control, driving speed control, plot,axis control for shield, Grouting control.(3)Through automation and artificial monitoring points in the layout section,conduct the monitor on projects of M15 line of road bed structure settlement, the rail differences settlement, the road bed and structure stripping, the rail displacement, the tunnel structure convergence, and soil body deep settlement. Based on construction and stable period monitoring data, analyze and discus the track traffic deformation actual value and compare the monitoring cumulative value and deformation warning value for the monitoring of M15 line of security state and testing the validation of numerical simulation results.