Chengshi guidao jiaotong yanjiu (Feb 2024)
Influence Analysis of City Railway Large-diameter Shield Parallel Construction on Adjacent High-speed Railway Subgrade Deformation
Abstract
[Objective] The large-diameter shield section on Shanghai City Railway Airport Link Line is parallel to the existing Shanghai-Hangzhou High-speed Railway. Due to strict deformation control requirements of high-speed railway subgrade, it is necessary to conduct in-depth research on the influence law of subgrade deformation caused by large-diameter shield parallel construction on existing high-speed railway. [Method] Based on Shanghai City Railway Airport Link Line engineering, in the process of large-diameter shield parallel construction, through field-monitoring of the existing high-speed railway subgrade, the land subsidence and the high-speed railway subgrade base plate displacement are monitored respectively. Based on field measurement data, the influence law of large-diameter shield parallel construction reinforced with portal isolation piles on soil disturbance and high-speed railway subgrade deformation is analyzed. [Result & Conclusion] Upon completion of shield construction, the maximum land subsidence occurs right above the tunnel, with ground heave at far end from the high-speed subgrade and land subsidence at the closer end. The maximum total land subsidence during and after the shield construction process is 21.14 mm and 20.32 mm, respectively, meeting control requirements. The effect of shield construction on ground vertical displacement is mainly concentrated within 20 m before the cutterhead reaching the section and within 50 m after it passes the section. Portal isolation piles can effectively restrict the displacement of the soil mass outside piles, control high-speed railway subgrade deformation, thus providing good isolation effects. After the completion of shield construction, the maximum horizontal and vertical displacements of Shanghai-Hangzhou High-speed Railway subgrade are both 1.9 mm, indicating that the parallel shield construction did not affect the normal operation of Shanghai-Hangzhou High-speed Railway.
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