Study on the Influence of Double-Line Overlapping Tunnel Construction Via Concealed Excavation on Ground Settlement
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 con-struction.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 in-versely 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 sub-stantially 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.
万方数据
维普
