繁华市区含水地层水平冻结及暗挖法施工  

The Technique of Horizontal Freezing and Underground Excavating Within Water Bearing Soft Soil in Busy Sections of a City

作　　者：汪崇鲜[1] 楼根达[1] 马玉峰[1] 

机构地区：[1]煤炭科学研究总院北京建井研究所,北京100013

出　　处：《冰川冻土》2000年第3期278-281,共4页Journal of Glaciology and Geocryology

摘　　要：结合上海繁华市区内地铁建设工程实践，介绍了含水软粘土地层中水平冻结加固和暗挖法施工技术．在借鉴传统地层冻结法的基础上，应用新近开发的冻结孔孔口密封装置、组合钻头以及“跟管”钻进技术，解决了含水软粘土地层中水平冻结管铺设的关键技术；采用特制的低温伸缩接头，解决了超长距离盐水干管在盐水降温过程中的冷缩问题；应用“新奥法”原理，通过设置土体冻胀卸压孔、冻土融沉注浆技术、合理的支护技术等综合技术措施，将地表沉降和地铁隧道最终位移控制在１０ ｍｍ以内。该技术在我国上海繁华市区内首次应用成功，为我国城市建设中繁华市区的地下工程建设提供了新的途径．In the light of the project of Shanghai Subway Line 2 in busy sections. this article describes a horizontal freezing technique for ground reinforcing and a method of underground excavating within water bearing soft soil. Under the basis of the traditional ground-freezing method, a new combined technique of sealed-device on the orifice of freezing-hole, assembled-aiguille and 'following-pipe' infixing is employed to lay horizontal freezing-pipes in water bearing soft clay, as a key-technique. A special low temperature flexing tie-in is used to solve the coldly-shri nking matter of over-long saltwater tube in the process of lowering saltwater temperature. The principle of' New Austria Method' is applied to underground excavation. And a series of technological measures, such as setting discharging-pressure bore on frozen-expanding soft-clay, melted-settling grouting technique of frozen clay, and rationally reinforcing technique, are used to control the settlement of the ground surface within the range of 10 mm and the ulti- mate displacement of metro tunnel. Freezing boreholes are arranged in all directions, and the space between the boreholes is less than 0.6 m. The cross-section is a rectangle with a frozen wall of l.2 m in thick and a mean temperature of -8.0℃. The colding liquors is saltwater in the temperature of -24-26℃ and the freezing time is 40 d for active frozen period and 35 d for maintenance period. After a horizontal freezing processing, the underground excavation begin. A successful example is the Shanghai Subway Line 2 constructed in busy sections. Thus a new way for construction within water bearing soft soil under busy sections of a city in China is put forward.

关 键 词：地铁旁通道 水平地层冻结 暗挖法 含水地层 隧道 

分 类 号：U455.49[建筑科学—桥梁与隧道工程]