地铁车站风亭组三角形分布隧道开挖影响分析

Excavation influence of triangular-distribution tunnels for wind pavilion group of a metro station

贵阳地铁2号线观水路站隧道工程为减少主体隧道开孔数量,将风亭组搬出主体隧道,在主体隧道入口处以三角形布局开挖风亭组。通过有限元软件ABAQUS建立三维模型研究了不同三角形布设隧道群开挖方案对地表沉降和隧道稳定性的影响。本研究的目的是揭示支护结构和围岩中地表沉降、变形和受力的变化规律,确定适合该种隧道布局的最佳开挖方案。结果表明,为控制地表沉降和支护结构变形,最佳开挖顺序为先开挖上部新风排风隧道,再开挖下部区间隧道。为控制支护结构的应力,最佳开挖方案是先开挖下部区间隧道,然后再开挖上部新风排风隧道。在本工程中,隧道最合理的开挖顺序为自上而下。隧道的最合理贯通厚度为5 m。

For the Guanshui Road Station tunnel project of Guiyang Metro Line 2,the wind pavilion group was moved out of the main tunnel to reduce the number of openings in the main tunnel,and the wind pavilion group was excavated in a triangular configuration at the entrance of the main tunnel.Based on the finite element software ABAQUS,a three-dimensional model is established to study the influence of different triangular-distribution tunnels excavation schemes on the surface settlement and tunnel stability.The objective of this study is to reveal the change rules of surface settlement,deformation and force in the support structures and the surrounding rock and identify the best excavation scheme for this tunnel configuration.Results show that to control the surface settlement and the deformation of the support structures,the optimal excavation sequence involves excavating the upper fresh air exhaust tunnel before the lower running tunnel.To control the stress of the support structures,the optimal excavation involves excavating the lower running tunnel before the upper fresh air exhaust tunnel.In this project,the most reasonable excavation sequence of the tunnel is from top to bottom.The most reasonable thickness of tunnel penetration is 5 m.