Application of AGF in Underground Excavation Construction of Water-Rich Sand Layer

被引：0
|
作者：
Mei Y. [1 ,2 ]
Zhao L. [1 ,2 ]
Zhou D. [1 ,2 ]
Liu J. [3 ]
Zhu J. [3 ]
Zhu J. [3 ]
机构：
[1] School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, Shaanxi
[2] Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering, Xi'an, 710055, Shaanxi
[3] The Third Engineering Co., Ltd. of China Railway Seventh Bureau Group Corporation, Xi'an, 710032, Shaanxi
来源：
Zhongguo Tiedao Kexue/China Railway Science | 2020年 / 41卷 / 04期
关键词：
Collapsible loess; Construction; Freezing method; Subway: Cross passage; Water-rich sand layer;
D O I：
10.3969/j.issn.1001-4632.2020.04.01
中图分类号：
学科分类号：
摘要：
A subway cross passage project in Xi'an was taken as the research object, which adopted the artificial ground freezing (AGF) as the auxiliary construction method for the underground excavation of cross passage. Based on the measured data and numerical simulation, the temperature field, stress field, frost heave and thaw settlement regularity of the soil mass in the AGF construction of the water-rich sand layer in a collapsible loess area were studied. Results show that in the active freezing period, the closer is to the inner side of the frozen soil wall, and the more frozen pipes are arranged around it, the faster the development rate of the frozen wall will be. During the active freezing period, the cooling gradient of soil increases with the increase of radial depth. The pressure relief hole plays a significant role in releasing frost-heaving force and controlling frost-heaving displacement of the frozen soil wall. The sudden change of pressure in the pressure relief hole can be used as a criterion for judging the closure of frozen soil wall. The active freezing period calculated by the slowest development rate of frozen soil tends to be conservative. At the same time, the average temperature of frozen soil wall in construction of water-rich sand layer by AGF method in collapsible loess area can be estimated by "ice forming formula method". After soil excavation, the frozen soil wall on the inner wall of cross passage will move to the inner side of the cross passage. There are three kinds of errors in the finite element calculation results of the frost-heaving displacement of the inner wall of the cross passage after soil excavation, namely, the error of measurement range, the error of geo-stress balance and the error of excavation size. The first two kinds of errors can be reduced by adjusting the measurement range of the finite element calculation results. © 2020, Editorial Department of China Railway Science. All right reserved.
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页码：1 / 10
页数：9
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