暗挖地铁隧道下穿输水管廊结构变形分析

Structural Deformation Analysis of Underground Subway Tunnel Passing Through Water Pipe Gallery

依托北京地铁14号线郭庄子站—大井站区间暗挖段下穿南水北调管廊工程,建立了隧道-围岩相互作用分析模型,对管廊变形进行施工全过程分析。研究结果表明:该工程选择两台阶三步法,进尺0.5 m,预留核心土距掌子面2 m,上下台阶间距5 m,左右线掌子面间距25 m,辅助袖阀管注浆方案较为合理。经过径向注浆加固,管廊最终沉降量明显减小,差异沉降及倾斜度均满足设计要求。两台阶三步法施工过程中,上下台阶开挖所引起的管廊变形量占管廊总变形量的93%,说明在开挖阶段采取注浆加固或者及时封闭成环能够有效抑制管廊变形。

Based on the underground excavation section of Guozhuangzi Station-Dajing Station of Beijing Metro Line 14 passes through the South-to-North Water Transfer Pipe Gallery,the tunnel-surrounding rock interaction analysis model is established,the deformation of the tunnel gallery is analyzed in the whole construction process.The research results show that two steps and three steps method,footage 0.5 m,reserved core soil 2 m away from working face,upper and lower steps 5 m apart,left and right line 25 m apart,auxiliary sleeve valve pipe grouting scheme is more reasonable.After radial grouting reinforcement,the final settlement of the pipe gallery is obviously reduced,and the differential settlement and inclination meet the design requirements.In the process of two-step and three-step construction,the deformation of pipe gallery caused by excavation of upper and lower steps accounts for 93%of the total deformation of pipe gallery,which shows that grouting reinforcement or timely sealing into a ring can effectively restrain the deformation of pipe gallery in the excavation stage.