崇文门站顶管预支护方案三维有限元分析

Analysis of Scheme on Technical of Pipe-Jacking Pre-Support in Chongwenmen Subway Station with Three-Dimensional Finite Element

北京地铁五号线崇文门站,下穿既有地铁一号线区间隧道,车站顶板与区间隧道底板间距2.858 m.为了严格控制既有环线区间隧道的沉降,确保环线地铁运营安全,首次采用了顶管作超前预支护.考虑不同的顶管直径以及周围地层的弹性模量对地表、拱顶和既有线的变形影响,用3D_Sigma三维有限元软件进行施工效应的计算模拟,掌握顶管预支护洞室的力学效应,预测车站施工引起既有隧道的沉降量.计算表明用大刚度的顶管作超前预支护,可以满足既有线地铁运营和城市地表建筑物变形控制要求.

Chongwenmen Station of No. 5 line of Beijing subway goes beneath the existing No. 1 line of the interval tunnel of Beijing subway. The distance between the roof of the station and the bottom board of the interval tunnel is 2. 858 m. In order to control the subsidence of the interval tunnel and guarantee the safety of operation strictly, pipe-jacking is used as pre-support for the first time. Threedimensional finite element software, 3D-Sigma, is used to calculate and simulate the construction effect. The mechanical effect of the hole room with pipe-jacking pre support is grasped well in this paper. In addition, the subsidence of the interval tunnel because of the construction of the station is forecasted. The computation indicated that pipe-jacking being used as pre-support can satisfy the request of distortion controlling for existing subways and city buildings.