近间距重叠隧道施工对桥桩变形影响研究

以武汉4、6号线某区间在建地铁为背景,运用FLAC2D数值模拟方法,研究了平面应变条件下近间距重叠隧道施工在不同地层损失率、不同开挖顺序下对铁路桥群桩基础的变形影响.数值模拟结果表明,地层损失率为0.2～1.5%时,盾构隧道开挖引起的铁路桥群桩基础变形满足安全要求;当地层损失率大于1.5%时,为有效控制邻近群桩基础变形,应采取相关方案,预先加固隧道周边土体不失为一种方法.

Research on the Deformation of the Bridge Piles Foundation due to Overlapping Tunnel Excavation

Based on the under-construction Metro Line 4 and 6 of Wuhan,an FLAC two-dimensional numerical model was established and the deformation of the railway-bridge pile foundation caused by different loss rates of stratum and excavation sequences of shield tunnel was studied profoundly.According to the results of numerical simulation,when the loss rate of stratum is between 0.2% and 1.5%,the deformation satisfies the safety requirements.However,when the rate is greater than 1.5%,measures must be taken to control the deformation of the railway-bridge pile foundation and the pre-reinforcement of soil around the tunnel is a recommended way.