地下道路建设对下方地铁隧道结构的影响分析

Impact of the Underpass Construction on the Underlying Subway Tunnel Structure

地铁隧道结构上方基坑开挖土体卸载会扰动基坑周围土体,引起周围土体应力场的改变,从而导致基坑下方地铁隧道结构变形。根据基坑开挖对隧道结构影响的计算变形值,优化施工开挖方案,提出有效的保护措施确保地铁隧道结构安全和运营安全。计算和实测结果表明,适当对地基土进行加固,采用抗拔桩及抗隆起板,分层分块开挖可有效控制基坑下方地铁隧道的变形;施工中选取对周边环境影响小的施工工艺、信息化施工是地铁保护不可忽视的重要因素。采取的控制基坑下方隧道结构变形设计方法和施工措施可以为同类工程建设提供参考。

The foundation excavation above the tunnel structures will change the stress field due to the unloading of soils and disturb the adjacent soils surround the excavated area.Therefore,the tunnel structure might be adversely affected by the construction above.This paper proposes the optimized deep excavation method and sequences that can ensure the safety of the tunnel structure as well as the operation safety.Both the analysis and construction monitoring results indicate that the appropriate soil improvement at the bottom,utilizing the uplift piles,slabs that can resist the buoyancy,appropriate layered and zone excavation are the effective ways to control the deformation of the underlying tunnel.During the excavation,it is also important to select the construction method that having minimal impact to the adjacent environment and to utilize the informational construction methods that providing real-time feed back to the proposed construction.