类矩形盾构施工对地表及桩基影响三维分析

3D analysis of the impact of quasi-rectangular shield tunneling on ground and pile foundation

为探究类矩形盾构法隧道施工对地表及桩基影响的规律,依托宁波轨道交通的某工程设计通过三维有限元软件,从隧道施工引起的土体位移、对邻近桩基影响方面分析,并与传统单圆双隧盾构法作对比,研究了类矩形隧道全断面掘削对周围环境影响规律.结果表明:类矩形盾构隧道沉降曲线近似正态分布曲线,地表变形及影响宽度小于相同情况的单圆双隧道,但在浅埋情况下影响较大;随着隧道埋深越深,类矩形盾构掘进造成的地表变形和桩位移越小;隧道在桩端以上约1/3桩长处施工对桩弯矩影响较大.

In order to explore the regularity of the influence of the quasi-rectangular shield tunnel construction on ground surface and pile foundation,based on the design of a tunnel project in Ningbo,this paper studied the influence of the tunnel on the surrounding environment using 3 D finite element analysis software---MIDAS GTS and established three-dimensional finite element model of the quasi-rectangular shield tunneling.According to the analysis of the displacement of soil and adjacent pile,the influence of the quasi-rectangular shield whole section cutting on the surrounding environment in contrast with the traditional segmental tunnel were discussed.The results show that the subsidence curve of the quasi-rectangular shield tunnel approximates normal distribution curve,and the surface deformation and influence width is smaller than that of single circular double tunnel under the same conditions,but the influence is greater in the case of shallow burial.With the depth of the tunnel,the surface deformation and pile displacement caused by the rectangular shield tunneling are smaller.The construction of tunnels at about 1/3 of the length of piles above the pile end has a great influence on the pile bending moment.