市域铁路大直径盾构并行施工对邻近高铁路基变形影响分析

Influence Analysis of City Railway Large-diameter Shield Parallel Construction on Adjacent High-speed Railway Subgrade Deformation

[目的]上海市域铁路机场联络线大直径盾构段与既有沪杭高铁并行。由于高铁路基变形控制要求严格,因此需对大直径盾构并行施工对既有高铁线路的路基变形影响规律进行深入研究。[方法]依托上海市域铁路机场联络线工程,在大直径盾构并行施工过程中,对既有高铁线路路基进行现场监测,分别监测地面沉降以及高铁路基底座板位移。根据现场监测数据,分析了门式隔离桩加固下大直径盾构并行施工对土体的扰动及对高铁路基变形的影响规律。[结果及结论]盾构施工完毕后,地面最大沉降位于隧道正上方,远离高铁路基侧地面变形为隆起,靠近高铁路基侧地面变形为沉降;盾构在施工过程中和施工完毕后,地面总沉降最大值分别为21.14 mm和20.32 mm,均满足控制要求;盾构施工对地面竖向位移的影响主要集中在刀盘到达断面前20 m和通过断面后50 m内;门式隔离桩能有效限制桩外土体位移,控制高铁路基变形,具有良好的隔断效果;盾构施工完毕后,沪杭高铁路基水平向和竖向位移最大值均为1.9 mm,说明盾构并行施工未影响沪杭高铁的正常运营。

[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.