关键词: 盖挖逆作法, AM桩, 有限元分析, 差异沉降, 地铁车站

Abstract: During the construction of underground structure by cut and cover topdown method, the horizontal displacement of underground diaphragm wall and the differential settlement of retaining structures are overlarge, which would affect the structure. Hence, the stress and deformation of a largescale metro interchange station constructed by cut and cover topdown method are numerically simulated by general finite element software ABAQUS. And then the deformation of underground diaphragm wall, differential settlement between AM pile and underground diaphragm wall and the axial force distribution of AM pile are calculated and analyzed. Finally, the advantages of AM pile in controlling the structure deformation and differential settlement are discussed. The results demonstrate that: (1) The floor has a better limiting effect on the horizontal displacement of underground diaphragm wall. (2) The differential settlement gradually increases with the construction progress, and the maximum value occurs when excavating the bottom soil, which is the worst condition that should be sealed. (3) Under the same pile length and diameter, the AM pile is superior to others in terms of structural deformation and differential settlement control. The study results can provide reference for similar projects in the future.

Key words: cut and cover topdown method, AM pile, finite element analysis, differential settlement, metro station