关键词: 地铁隧道, 有限元法, 数值分析, 沉降, 内力

Abstract: 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.

Key words: metro tunnel, finite element method, numerical analysis, settlement, internal force