地铁隧道穿越角度对地表建筑物的影响分析

结合深圳地铁隧道下穿某住宅小区建筑群的工程实践，以某框架结构建筑为研究对象，按照隧道-土体-结构共同作用，利用Midas/GTS软件建立三维非线性有限元模型，计算了隧道轴线与地面建筑物成90º、60º、45º和30º夹角4种不同工况，分析隧道轴线与建筑物不同夹角条件下隧道开挖对地表建筑物基础沉降和结构受力变形分布形态的影响。计算结果表明，隧道以不同角度穿越时，地表建筑基础的沉降过程和分布形态差异明显。随着穿越角度? 的减小，基础沉降最大增幅为37.3%，建筑基础沿线沉降由对称分布转为侧向倾斜，相邻柱基沉降差增大；建筑倾斜和扭曲变形增加明显，最大增幅达10倍；由于分析部位不同，相比建筑基础及底部结构变形而言，隧道穿越角度的改变对建筑内力影响较小。

Analysis of influence of metro tunnel crossing angles on ground buildings

Based on the practice of a metro tunnel crossing below ground buildings in Shenzhen soft soils, taking a frame structure residential building for example, a 3D nonlinear constitutive model that consists of the tunnels, surrounding soils, the building and its foundation is established by finite element program MIDAS/GTS. The four conditions of the crossing angle of 90°, 60°, 45° and 30° between tunnel axis and the ground building have been calculated; and the regularities distribution of the building foundation settlements and the structure deformations and stresses due to excavation under different conditions have been analyzed. The results indicate that there are obvious differences in the settlement process and distribution of foundation when the metro tunnel crossing through the building under different crossing angles. With the decrease of crossing angle α, the settlement of foundation rises by 37.3% at most; and the surface settlement of foundation changes from symmetrical distribution to lateral tilt; and the differential settlement of adjacent plinth increases obviously. Tilt displacements and distortion of building increase significantly under different crossing types; and it could rise 10 times at most. Compared with the deformation of the building foundation and the bottom of structure, the influence of changes of crossing angles on internal forces of structure of the building is light.