92
施工技
术
CONSTRUCTIONTECHNOLOGY
2013年1月下第42卷，第2期
土压盾构在砂性土中施工关键技术研究
王新，沈奇2
200065）
(1.上海城市建设设计研究总院，上海200125；2.上海城建市政工程（集团）有限公司，上海
【摘要】对杭州地铁2号线区间段施工进行现场跟踪，提出砂性土中盾构施工的主要技术难题，并对施工中的关键技术进行了总结分析。其中采取放慢推进速度均匀推进、改良同步注浆材料、加强二次补浆管理和对注浆补浆设备养护等措施能够较好地控制地表沉降。向刀盘前方注人膨润土浆液，并通过泡沫改良土稳定土压，持续出土。向刀盘前方和盾构侧面注人膨润土浆液，可以降低盾构推力和减小刀盘弯矩。采取有效降水止水措施可减少加固薄弱区可能造成的工程风险。
【关键词】隧道工程；土压平衡；盾构；砂性土；施工技术
[中图分类号】TU455
【文献标识码］A
【文章编号】1002-8498(2013)02-0092-03
StudyofKeyTechnologyonEPBShieldConstructioninSandySoil
Wang Xin',Shen Qi2
(1. Shanghai Urban Construction Design & Research Institute,Shanghai 200125, China;
2. Shanghai Urban Construction Municipal Engineering (Group) Co. , Lad.,Shanghai 200065, China)
Abstract: In this paper, the scene of Hangzhou Metro Line 2 interval segment construction was tracked, and the main technical problems were proposed which shield constructed in sandy soils. Then the key technology of construction was analyzed. Taking to slow down the advanced speed and uniform propulsion, improved synchronization grouting material, to strengthen management of the secondary slurry and equipment maintenance were better measures to control surface settlement. Bentonite slurry which was injected into the front of the cutter, and the soil improved by foam were used to stabilize the soil pressure and transport out of soil continued. Injecting bentonite slurry into the, front and side of the shield could reduce the thrust of the shield and reduce the moment of the cutter. Taking effective precipitation and
sealing measures can reduce the risk of the project may be caused by weak areas reinforced. Key words :tunnels; earth pressure balance; shields; sandy soil; construction
工程概况
杭州地铁2号线建设三路站~建设一路站区间
长约973m，由1台盾构自建设三路站工作井始发，沿市心北路推进，至建设一路站工作井进洞，然后调头反向推进至建设三路站南端井完成掘进。隧道结构外径6.2m，内径5.5m，采用C50的预制管片
拼装而成。隧道埋深9.65~16.2m。 2工程与水文地质条件
上行线盾构在1~100环、655~809环全断面均在砂性土中掘进，掘进土层主要为③-层砂质粉土夹黏质粉土、③-层砂质粉土夹粉砂、③，淤泥质粉质黏土。土层主要物理参数如表1所示。掘进土层土质不均匀，土面粗糙，渗水性好，干强度低，饱
【作者简介］王新，工程师，E-mailzicaihaoya@163.com
【收稿日期】2012-03-28 万方数据
和状态下受振动荷载的作用容易产生液化现象，含水量增大后易产生流动，出现塌方。
场区浅部地下水属松散岩类孔隙潜水，主要赋存于上部填土层及③类粉砂层中。本场区潜水静止水位一般深0.9~2.2m。
技术难点分析 3
1)地面沉降不易控制，注浆量较大
表1盾构穿越土层主要物理参数
Main physical parameters of shield crossing soil
Table1
渗透系数/
土层编号
土层名称
③砂质粉土夹粘质粉土
?
砂质粉土夹粉砂淤泥质粉质黏土
重度/(kN-m-)
19.6 18.9 17. 4
含水量/%
26.5
(10 -*cm*s -)
水平 1.80
23. 4
2.20
41. 6 ~41.8 0. 012
整向 1.60 2.00 0. 01