盾构隧道侧穿高架桥桩基条件下群桩遮拦效应分析

摘要

为了研究土体c（黏聚力）、φ（内摩擦角）和桩隧间距X对群桩遮拦效应的影响，以合肥轨道交通1号线盾构隧道近距离侧穿高架桥桩基群工程为背景，采用三维数值分析方法，分析了盾构掘进过程中桩基的变形规律，得出以下结论：1）桩基的位移随着盾构开挖面的靠近逐渐增大，当盾尾离开桩基所在平面后逐渐稳定；2）土体的c、φ值对群桩桩基水平位移、竖向位移和轴力的遮拦效应影响比较大，c、φ值越大群桩遮拦效应越不明显；3）桩隧间距X对桩基水平位移和轴力遮拦效应影响较为明显，X越小桩体变形和受力越复杂，群桩遮拦效应越明显。%The deformation rules of pile foundation of viaduct induced by shield tunneling nearby are analyzed by 3 D numerical analysis method,so as to learn the influences of soil cohesive strength c,internal friction angleφand distance between pile and tunnel axial line X on shielding effect of a pile group,by taking shield tunnel of Hefei Metro Line No.1 crossing nearby pile foundation of viaduct for example.Some conclusions are drawn as follows:1 ) The displacement of the pile foundation increases with the distance between pile foundation and shield head decreases;and the displacement of the pile foundation becomes stable when shield tail passed.2 )The c and φof soil affect the shielding effect of pile group to horizontal displacement,vertical displacement and axial force a lot;and the shielding effect of pile group decreases with the c orφincreases.3 )The influence of X on shielding effect of pile group to pile foundation is obvious;and the shielding effect of pile group decreases with the X decreases.