隔离桩在隧道侧穿邻近浅基建筑中的应用

Application of Isolation Piles on Metro Tunnel for Side-Crossing the Buildings with Shallow Foundation

针对某地铁新建隧道侧穿邻接浅基建筑采用隔离桩隔离的工程,进行了正交有限元法优化研究.先对比分析了既有建筑对隧道施工引起地表沉降的影响,使用隔离桩(模拟中采用经验隔离桩参数)的隔离效果,以及注浆对隧道稳定性的影响.然后,采用正交有限元方法对隔离桩3个主要参数进行优化设计.研究结果表明:既有建筑的存在改变了原自由地面的沉降槽形状,使变形和支护结构内力增大,隔离桩的打设和注浆对变形和内力有一定的控制作用.隔离桩最优参数为桩长33 m,桩纵向间距0.5 m和桩距离隧道1.5 m.对桩的参数优化分析对于以后的类似工程有一定借鉴意义.

The mechanical behavior and deformation of a metro tunnel using isolation piles adjacent to existing buildings with shallow foundation were studied with orthogonal finite element analysis method.Comparative analysis was implemented to examine：the settlement at the surface of existing building,the isolating effect of isolation piles and effectiveness of grouting on tunnel stability.Orthogonal finite element analysis was adopted to optimize three main parameters of isolation piles.The present results indicated that the existing building changes the shape of settlement trough and increases the inter-force and deformation.Isolation piles and grouting have some control on the deformation and inter-force of supporting structures.The optimal parameters of isolation piles are 33 m in length,0.5 m in longitudinal spacing,and the distance between piles and tunnel is 1.5 m.This kind of optimization may provide references for the similar construction design.