Study On Security Construction Control Of Small Space Overlapped Shield Tunnel

Due to the constraints of urban traffic corridor, the City subway tunnel through the tunnel are often forced to use overlapping,and more of the construction method are shied, therefore, small space overlap shield tunnels are frequent.Considering the difference of design and construction difficulty and sphere of influence between ovlerlap and single tunnel, and shield construction method is also different from mine construction. Based on the foregoing summary,taking into account of the the excavation face support pressure, shield force and the cutter torque,coniothyrium friction with the soil,digging shield over,tail gap tail shield grouting, hardening of the grout and so on,a detailed analysis of force and torque durning shield construction,establish a reasonable simulation of shield tunneling. This article combined with the Shenzhen Metro Line HongLao-LaoShai interval, the following aspects were studied:(1)Compare domestic and foreign small space subway tunnel construction method, combined with numerical simulation, proposed the construction of shield tunnel in Shenzhen Metro Line overlap tunnel。(2)Analyze in-depth various of force and torque in shield construction, from the four-stage construction process simulation, establish a fully reflect the whole process of Shield Tunneling Method of three-dimensional simulation.Through comparison of Ground movement, stress, internal forces and other aspects both in up-hole-first and down-hole-first, determine the down-hole-first construction sequence.(3)Combine the construction sequence relationship between houses and tunnel in ShenZhen Metro HongLao-LaoShai interval,analyze the house loads impact on construction sequence and damage to houses.(4)Background to the Shenzhen Metro, analyze the the tunnel horizontal impact in three main conditions (horizontal parallel, vertical overlap, oblique 45 degrees),then partition base on this. Also consider the impact of vertical distance, and draw horizontal and vertical adjacent affecting chart of shield overlap tunnel.(5)Propose construction of protective measures and compare and calculate the strengthening program of "cross support" and the "hydraulic platform vehicle", select the appropriate reinforcement.(6)Combine parameters of engineering train to calculate with dynamic load train.(7)Propose a project monitoring and measurement standards for this project after calculation.