开挖过程及围护结构对地铁车站抗震性能的影响

为了研究开挖工序以及围护结构作为永久结构在明挖车站的抗震设计校核中的作用,基于以灌注桩作为支挡结构的郑州市某明挖结构地铁站,采用Plaxis2D建立二层单柱双跨矩形框架式有限元模型,采取硬化土本构,建立考虑分步开挖、和不考虑开挖的模型,进行有无围护墙及不同墙厚抗震验算.研究结果表明:侧墙作为主要抗侧力构件,在地震荷载作...

Influence of Excavation and Retaining Structure on the Seismic Performance of Metro Stations

This study aims to determine the effect of excavation process and retaining structure as a permanent structure in the seismic design of open excavation metro stations. A finite element model of two-story two-span rectangular frame is established by Plaxis2D based on an open cut subway station with cast-in-place pile as the retaining structure in Zhengzhou City. The constitutive model of hardening soil is adopted to assess earthquake resistance. Results showed that under seismic load, the design value of the upper bending moment of the structure is 31% smaller without considering excavation than that considering excavation. The design of the side wall and floor is conservative, with bending moments larger than 87% and 64%, respectively. If excavation is neglected, then the calculation error of shear force on the lower sidewall increases with the depth from 36% to 122%. However, the influence of stiffness reduction of the diaphragm wall on the internal force is less than 5%. Therefore, in the seismic design of structures on this kind of soft soil, the influence of excavation and the diaphragm wall within the design life should be considered. The bottom of the shear wall and the top and bottom of the middle column should also be emphasized.