综合管廊近距离上穿盾构隧道施工影响分析及控制技术

Construction Influence Analysis and Control Technology of Utility Tunnel Crossing Shield Tunnel at Close Distance

以综合管廊垂直近距离上穿地铁盾构隧道为背景,分析了综合管廊施工对地铁盾构隧道的主要影响,提出了关键控制措施,通过数值模拟分析了基坑坑底加固厚度对下卧盾构隧道变形影响,得出了地层加固的经济厚度,并与现场实测数据对比,很好的印证了分析结果,能够为类似工程提供借鉴。研究结果表明:①综合管廊垂直上穿盾构隧道应重点控制开挖卸载导致的盾构隧道隆起变形,可以通过坑底地层加固、增加围护桩嵌固深度、分层跳槽开挖、及时浇筑结构等措施进行控制。②采用数值模拟获得的地层经济加固厚度,能够在保证地铁结构安全的同时节约工程造价。③沿着盾构隧道纵向的竖向变形表现出“中间高、两边低、对称于管廊基坑中轴线”的规律。

Taking the context of comprehensive utility tunnel vertically passing through the subway shield tunnel at close proximity,the main impacts of comprehensive utility tunnel construction on the subway shield tunnel are analyzed,and key control measures are put forward.The influence of the reinforcement thickness at the excavations bottom on the deformation of the underlying shield tunnel is analyzed by numerical simulation,and the optimal thickness of the stratum reinforcement is determined.By comparing the field measured data,the analysis results are confirmed,which can provide reference for similar projects.The research results show that:①The comprehensive utility tunnel should focus on the control of the uplift deformation of the shield tunnel caused by excavation and unloading when it vertically crosses the shield tunnel.This can be achieved through measures such as reinforcing the bottom layer of the excavation,increasing the embedded depth of the retaining pile,implementing stratified trench excavation,and timely pouring of the structure.②The economic reinforcement thickness of the stratum can be obtained through numerical simulation,which can ensure the safety of subway structure and save the project cost.③The vertical deformation along the longitudinal direction of shield tunnel exhibits a pattern of being higher in the middle,lower on both sides,and symmetric with the central axis of the utility tunnel excavations.