深埋盾构隧道受力特性有限元研究与分析

Finite element study and analysis on mechanical characteristic of shield tunnel with buried depth

本文以地层结构法为基本研究方法,基于地铁盾构隧道埋深、管片接头处橡胶材料以及地面堆载三个基本因素的影响,对地铁盾构隧道衬砌管片、管片接头及管片接头处橡胶垫层的应力、应变及变形开展有限元分析。有限元分析中采用包含衬砌管片、管片接头处橡胶垫层及周围土体的三维实体有限元模型。研究结果表明:地铁盾构隧道整体衬砌管片和橡胶垫层的应力、应变及变形是相对均匀的;管片接头处出现的不连续位移,随隧道埋深的增大而增大,随橡胶垫层弹性模型的增大而减小;管片接头处存在明显的拉应力集中现象,在埋深为75m以上时,集中拉应力超出钢筋混凝土管片的极限拉应力。该研究对以后地铁盾构隧道衬砌管片的设计具有一定的理论和实践价值。

The basic research method is stratigraphic structure method,which carrying out the finite element analysis for the stress,strain and deformation of subway shield tunnel lining segment,segment joint and segment layup rubber cushion layer,considering three basic factors of subway shield tunnel buried depth,the material of segment layup rubber and the ground heap load.This paper uses the three-dimensional entity finite element model,which includes the lining segment, the segment layup rubber layer and the surrounding soil.The result of this paper shows that the stress,the strain and the deformation of the whole subway shield tunnel lining segment and the rubber layer is relatively homogeneous; the segment joints appear discontinuous displacement,which increases along with the tunnel buried depth increases,with rubber layer elastic model decreases; the segment joints exist obvious tension stress concentration phenomenon,when tunnel buried depth over 75 meters,the concentrated tensile stress is beyond the limit of reinforced concrete segments tensile stress.The study has some certain theoretical and practical value on the subway shield tunnel lining segment design in the future.