MJS工法桩加固施工对运营隧道的影响研究

Influence study of MJS pile reinforcement construction on operational tunnel

随着国内主要城市轨道交通的大规模建设,建成线路越来越多,运营里程成倍增加,地铁的安全运营对一个城市的重要性不言而喻。近年来,市政隧道上跨、下穿运营轨道交通的工程日益增多。上方基坑开挖卸载会使下方的盾构隧道产生形变,为抑制这种变形,软土地区采用MJS工法桩基底及门式加固的工程越来越多。利用徕卡TM50/60测量机器人及地铁自动化监测系统(GeoMos-CN),实时监测下方运营隧道的变形数据,研究加固施工引起既有盾构隧道的变形特性尤显重要。本文结合杭州某软土地区上跨地铁基坑工程的实测数据,分析MJS工法桩加固施工过程中不同工况下既有运营盾构隧道的道床沉降、水平位移、管片收敛的变形特性,总结隧道变形规律,以便及时发现安全隐患,进而有效地保障人民群众的生命财产安全,为后续同类工程实践提供参考借鉴。

With the significant expansion of rail transit construction in major cities in China,an increasing number of tunnel lines have been constructed.The operational mileage has multiplied.The importance of ensuring safe subway operations within city is self-evident.In recent years,the number of municipal-service tunnel projects overcrossing or undercrossing operating tunnels has been increasing.Excavation in the lower soft soil layer will lead to tunnel deformation.To mitigate deformation,an increasing number of projects utilize the MJS construction method,which involves pile foundation and portal reinforcement in soft soil areas.It is crucial to employ the Leica TM50/60 measuring robot and the Automated Metro Monitoring System(GeoMos-CN)for real-time monitoring of operating tunnel deformation data and studying the deformation characteristics of existing shield tunnels resulting from reinforcement construction.This work examines the deformation characteristics,including tunnel settlement,horizontal displacement and horizontal convergence,resulting from MJS pile reinforcement under varying conditions in the soft soil area of Hangzhou.It summarizes the laws governing tunnel deformation,which can facilitate the timely identification of safety hazards and ensure the safety of people and their property.Additionally,it serves as a valuable reference for future similar engineering practices.