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 3D numerical analysis method,so as to learn the influences of soil cohesive strength c,internal friction angle φ and 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 φ of 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 or φ increases. 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.