顶管法施工对地铁隧道的影响分析——以深圳某区间隧道施工为例

为研究大直径顶管上跨施工对地铁运营隧道的影响预测问题,以深圳地区1.8m大直径顶管上跨地铁1号线某区间隧道施工为例,采用MIDAS/GTS三维有限元软件建立三维数值模型,对顶管施工引起的地表隆沉、地铁隧道竖向位移和横向收敛变形、顶管隧道本身竖向位移进行数值模拟分析。分析结果表明,顶管施工过程中,由于土体开挖卸载引起下部土体向上回弹,导致地面会发生一定的隆起,最大隆起发生在顶管隧道两端,中部隆起位移较小;地铁隧道水平位移很小,竖向发生向上位移,并伴随横向收敛变形,导致地铁隧道发生竖椭圆变形,但其位移均在地铁保护的允许范围内;顶管隧道本身会发生竖向向上位移,易导致顶管隧道前端产生偏移。该结论可为类似工程施工项目提供参考。

Analysis of the impact of pipe jacking construction on subway tunnels:Taking a certain section of metro in Shenzhen as example

In order to study the impact of large diameter pipe jacking construction on the tunnel of metro, taking the 1.8 m large diameter pipe jacking across a certain section of metro Line 1 in Shenzhen as example, the three-dimensional finite element software MIDAS/GTS is used to establish a three-dimensional numerical model, then the earth surface upheaval, the vertical displacement, horizontal convergence deformation of subway tunnel and vertical displacement of pipe jacking tunnels caused by pipe jacking construction are numerically simulated. The results show that due to the soil excavation and unloading , the lower soil rebounds upwards, causing a certain uplift on the ground, the maximum uplift occurs at both ends of the pipe jacking tunnel and central uplift displacement is smaller. The horizontal displacement of metro tunnel is very small, upward displacement in the vertical direction and transverse convergence deformation lead to vertical elliptical deformation of subway tunnel, however, the displacement is in the allowable range of subway protection. The vertical displacement of the pipe jacking tunnel will lead to the excursion at the front of the pipe jacking tunnel. The conclusion could provide reference for similar engineering construction projects.