水平MJS加固下盾构下穿既有车站底板变形研究  

Research on Floor Deformation of Shield Tunneling Through Existing Stations Under Horizontal MJS Construction

作　　者：张士强 ZHANG Shiqiang(China Railway 16th Bureau Group Beijing Rail Transit Engineering Construction Co.Ltd.,Beijing 100018,China)

机构地区：[1]中铁十六局集团北京轨道交通工程建设有限公司,北京100018

出　　处：《铁道建筑技术》2024年第9期155-158,163,共5页Railway Construction Technology

基　　金：中铁十六局集团有限公司科技研究开发计划项目(K2020-18C)。

摘　　要：为了合理地确定黏性土层水平MJS(Metro Jet System)施工时对既有车站的影响,保障工程安全,以苏州某新建地铁隧道近距离下穿既有车站为背景,阐述了水平MJS加固的设计、施工参数、监测点的布设;提出了一种水平MJS的数值模拟方法,分别研究其施工对既有结构变形的影响和其加固完成后盾构切削地连墙时车站的变形,并在依托工程中进行验证。结果表明:在盾构下穿车站区域采用向下180°摆喷Ф2.0 m水平MJS桩满堂加固,模拟预测水平MJS喷浆将使车站底板最大隆起2.77 mm(实际监测值为3.7 mm);切削地连墙的影响一般小于0.5 mm,盾构下穿的影响最大为1.5 mm;这都体现出水平MJS加固、盾构下穿车站的施工扰动小,满足既有车站底板的变形控制要求,相关经验值得借鉴。In order to reasonably determine the impact of horizontal MJS(Metro Jet System)construction in cohesive soil layers on existing stations and ensure the safety of the project,this study is based on the project that a new subway tunnel in Suzhou close crossing through the existing station,and explains the design and construction parameters of horizontal MJS reinforcement and the arrangement of monitoring points.A numerical simulation method for horizontal MJS is proposed to study separately the influence of its construction on the deformation of existing structures and the deformation of the station when the shield tunnel cuts through the diaphragm wall after reinforcement completion,and it is verified in the supported project.The results indicate that the area where shield tunneling through the station is reinforced using a full⁃cavity method with downward 180°swing⁃jetϕ2.0 m horizontal MJS piles,the simulation predicts that the horizontal MJS grouting will cause a maximum uplift of 2.77 mm on the station′s floor(actual monitored value of 3.7 mm).The influence of cutting through the diaphragm wall is generally less than 0.5 mm,and the maximum influence from the shield tunneling through is 1.5 mm.The engineering practice shows that the construction disturbance of horizontal MJS is small,which can meet the deformation control requirements of existing railway stations.The relevant experience is valuable and worth referencing.

关 键 词：地下工程 地层加固 水平MJS 盾构下穿 数值模拟 

分 类 号：U231.3[交通运输工程—道路与铁道工程]