摘要
北京地铁22号线定福庄站—管庄站双线暗挖叠落隧道工程安全风险极高,易产生严重变形和不均匀沉降问题,采用有限差分软件对隧道施工诱发地面沉降问题展开研究,基于现场监测数据证明模型的可靠性,并对不同施工方案的影响规律进行探讨。结果表明:模型计算结果与现场监测结果基本吻合,沉降差异较小,模拟结果准确可信。在施工过程中,监测点地面沉降随隧道下穿顺序依次开始增大,沉降量与隧道净距成反比,与距隧道开挖区域水平距离成反比,且沉降增量呈现两个阶段的变化特征,第一个阶段中位于砂土层中的下层隧道施工影响更加显著;不同施工方案诱发地表变形规律接近,下导洞开挖阶段变形增量相对较大,上导洞先施工的方案可显著减少最终地面沉降,施工条件允许时可以优先采用。研究结果可以为相关工程的沉降预测和施工方案选择提供参考。
The double-line overlapping tunnel project between Dingfuzhuang Station and Guanzhuang Station on Beijing Metro Line 22 adopts a concealed excavation method and presents extremely high safety risks,prone to severe deformation and uneven settlement.In this study,finite difference software was employed to investigate the ground settlement induced by tunnel construction.The reliability of the numerical model was validated based on field monitoring data,and the influence of different construction schemes was examined.The results indicate that the calculated settlements agree closely with the monitoring data,demonstrating minimal discrepancies and confirming the accuracy of the simulation.During construction,ground settlement at the monitoring points increases in sequence as the tunnel sections advance beneath them.The magnitude of settlement is inversely proportional to both the clear distance between tunnels and the horizontal distance from the excavation zone.Settlement increments exhibit two distinct phases,with the lower tunnel-located in a sandy soil layer-exerting a more significant influence in the first phase.Although different construction schemes produce broadly similar ground deformation patterns,deformation increments are larger during the excavation of the lower pilot tunnel.Notably,an"upper pilot tunnelfirst"approach can substantially reduce the final ground settlement and is recommended when construction conditions allow.These findings provide a valuable reference for predicting settlement and selecting construction schemes in similar tunnel engineering projects.
作者
李飞宇
LI Feiyu(China Railway 18th Bureau Group Municipal Engineering Co.,Ltd.,Beijing 100024,China)
出处
《国防交通工程与技术》
2025年第1期25-30,共6页
Traffic Engineering and Technology for National Defence
关键词
暗挖隧道
叠落隧道
数值模拟
地层变形
施工方案
concealed excavation tunnel
overlapping tunnel
numerical simulation
stratum deformation
construction scheme
