土岩复合地层盾构掘进对桥梁变形影响分析

Influence Analysis on Bridge Deformation Caused by Shield Construction in Soil-rock Compound Strata

依托深圳地铁11号线宝安—碧海湾区间盾构穿越桥梁桩基工程,采用FLAC3D有限差分软件研究土岩复合地层盾构近距离掘进对桥梁桩基础、桥面的变形影响规律及影响范围,并与实测结果进行对比。结果表明:隧道施工对周围地层的影响可划分为塑性破坏区、弹性区和无影响区3个区域;盾构隧道掘进引起的桥面沉降较大,盾构对桥面变形的影响范围为盾构掘进面距桥面为-5D～4D;位于2条隧道之间的桥梁桩基受到2条隧道的影响,桩身竖向位移较大,且最大竖向位移位于桩顶;位于隧道侧方的桩基,盾构施工引起的X方向水平位移值较大,且施工对其影响范围也更大,具有一定的滞后性。

Relying on the bridge pile foundation engineering of Baoan-Bihaiwan shield tunnel of Shenzhen Metro Line 11,FLAC3D software is used to research the influence rule and influence scope of the deformation of the bridge pile foundation and the bridge deck caused by shield tunneling from close range in Soil-rock compound strata,and the research is compared with the measured results.The results show that:The influence of tunnel construction on the surrounding strata can be divided into three areas:plastic failure zone,elastic zone and non-affected zone.Bridge deck settlement caused by Shield tunnel construction is larger,the influence scope of shield on bridge deck deformation is-5D to 4D from Shield tunnel excavation face to bridge deck;the bridge pile foundation between the two tunnels is under the influence of two tunnels,and the vertical displacement of the pile body is larger;the maximum vertical displacement is located at the top of pile;for the pile foundation located in the tunnel side,the horizontal displacement value in X direction is bigger,and the influence scope is wider caused by shield construction;and the influence has certain hysteresis.