双线盾构隧道施工对近接高架桩基的影响研究

Study on the Influence of Double-line Shield Tunnel on the Foundation of the Adjacent Elevated Pile

盾构法施工地铁隧道近距离侧穿既有运营城市轨道交通高架桥梁桩基时会扰动周围土体,其产生的附加应力导致桩基变形,给既有运营城市轨道交通带来安全隐患。本文以重庆轨道交通15号线大学城南站~陈家桥站盾构区间侧穿既有重庆轨道交通1号线高架桥桩基为例,采用abaqus有限元数值模拟软件,研究不同开挖顺序下双线盾构施工对桥梁桩基的影响。研究结果表明,双线贯通后,最大地表沉降值为1.89 mm,水平方向桩基最大附加位移为1.75 mm,且都出现在盾构中轴线附近。此外,盾构距离桩基越近,盾构掘进对桩基的影响越大,建议盾构始发时先进行距离桩基较远侧隧道,推行至安全距离后再进行距离桩基较近侧隧道。

When the shield method constructs the subway tunnel in close proximity to the pile foundation of the existing operating urban rail transit viaduct,the surrounding soil will be disturbed,and the additional stress generated by it will lead to the deformation of the pile foundation,which will bring potential safety hazards to the existing operating urban rail transit.In this paper,the existing Chongqing Rail Transit Line 1 viaduct pile foundation is taken as an example,and the influence of double-line shield construction on the bridge pile foundation under different excavation sequences is studied by using abaqus finite element numerical simulation software.The results show that the maximum surface settlement value is 1.89 mm,and the maximum additional displacement of the horizontal pile foundation is 1.75 mm,and both of them appear near the central axis of the shield.In addition,the closer the shield is to the pile foundation,the greater the influence of the shield tunneling on the pile foundation,and it is recommended that the shield starts the tunnel farther away from the pile foundation first,and then starts the tunnel closer to the pile foundation after the implementation to the safe distance.