Study on settlements control standards for shield tunneling beneath high-speed railway tunnels
Addressing the challenging issue of deformation control in newly constructed shield tunnelsbeneath high-speed railway tunnels, baced on three typical high-speed railway crossing projects of Shi-jiazhuang Metro Line 4, Line 5, and Beijing Metro Line 8, this study investigates the standards for controlling settlements and deformations beneath high-speed railway tunnels. Firstly, a refined ballast-less track-tunnel three-dimensional finite element model is constructed using the finite element soft-ware Midas GTS NX.The model calculates the structural internal forces under various settlement con-ditions induced by shield tunneling beneath cast-in-place tunnel, shield tunneling and U-groove sec-tion.It derives the allowable deformation values of structures meeting crack width limits and calculatesthe allowable deformation values of CRTS Ⅱ and CRTS Ⅲ track structures meeting specification lim-its.Subsequently, Abaqus software is employed to build a coupled vehicle-rail dynamic model, com-puting safety and comfort indexes of vehicles under different train speeds and settlement conditions, and deriving allowable values for track height and smoothness.Finally, the study consolidates the al-lowable deformation values of each structure and presents standards for controlling structural settle-ment and deformation.Results indicate that the allowable deformation values of existing structures, computed based on limits of structural crack width, 10 m chord length track height deviation, and dy-namics' most sensitive indexes, can serve as standards for settlement and deformation control of shield tunnels beneath high-speed railway tunnels.These standards can complement existing specifica-tions and provide valuable references for similar high-risk, high-demand projects involving high-speed railway crossings.
shield tunnel underpasshigh-speed railway tunnelsettlement deformationdeformation control standard
万方数据
维普
