浅埋富水断层带大跨暗挖车站注浆技术研究

Study on grouting technique for construction of shallow depth bored tunnel in high-pressure-water fracture zone

如何安全穿越富水断层带,在防止洞内涌水溃砂的同时,控制地表沉降,保护市政管线是城市地铁修建的一大难题。以青岛地铁4号线人民会堂站为例,对富水断层带大跨车站的注浆技术展开研究,通过比选不同方案,阐述了地表+洞内联合注浆理念并介绍了注浆的相关设计参数,整套施工流程及应急预案,并进行动态监测。研究结果表明:1)全幅路面注浆要求大量的地表钻孔,钻孔密集且倾斜,容易碰触管线,工期很长;2)传统的洞内帷幕注浆法存在钻孔溃砂风险,且开挖进度缓慢;3)地表+洞内联合注浆法工程量较小,平均月进尺22m,地表钻孔垂直且不会误触管线,该工法可有效加固破碎岩体,提高自稳能力,保证隧道施工安全,4)监测结果表明,采用联合注浆法的暗挖车站变形及地表沉降均在可控范围内,联合注浆法是安全可靠的。

It’s a reserach prioriy to run across the high-pressure-water fracuture tunnel while keeping municipal pipeline and ground intact. Based on Renmin Huitang station of Qingdao metro line 4,research about the grouting technique of large-span metro station in high-pressure-water fracuture zone was done. By comparing different grouting plan and combining real-time dynamic monitoring,expound the concept and details of underground-surface associated grouting technique,whole construction process and emergence plan. The results prove that: 1) the suface grouting require large quantities of boreholes,which is dense and inclined,having risks to break the municipal pipeline,and having a cost of time; 2) the standard inner full-section curtain grouting has dangers of borehole collapse of sand due to the fracture geology,besides,the excavation speed is also slow; 3) the project quantities of underground&surface grouting technique is less,the month-average drilling length is 22 m,the accosiated grouting technique requeires a little vertical drilling borehole whcih is safety to the pipeline. The technique has a effectively reinforcement on the broken rock,assuring tunneling construction safe; 4) the monitoring results indicate that,adopting the underground-surface associated grouting technique can matain the groung surface settlement and deformation of shallow depth bored tunnelling stationat a safe range.