ISSN 2096-4498

   CN 44-1745/U

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Construction Technology for Safe Excavation of HighHanging Portal of SichuanTibet Railway Near Primary Class I Water Source

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  • (1. China Railway Tunnel Group Co., Ltd., Guangzhou 511458, Guangdong, China; 2. School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, China; 3. School of Civil Engineering, Central South University, Changsha 410075, Hunan, China; 4. National Engineering Laboratory of High Speed Railway Construction Technology, Central South University, Changsha 410075, Hunan, China)

Online published: 2022-03-18

Abstract

 The construction of Longbagou inclined shaft in SichuanTibet railway faces the problems of highhanging portal, narrow site, broken surrounding rock, fragile ecology, alpine cold and hypoxia. In order to solve the above problems and ensure green, safe, and efficient construction of the project, some measures have been adopted during construction. Firstly, reasonable planning of the cave site, construction with slurry stone and gravity retaining wall, backfilling wall back and other measures are used, which not only protect the ecological water source but also overcome the problem of narrow construction work site. Then, the active and passive protection network is applied on the roof of the cave, pipe roof and the guide wall to move the cave entrance ahead, and the elevated concrete retaining wall is constructed at the foot of the cave entrance slope. The above measures are adopted to ensure the stability of the elevation slope of the cave entrance, forming the technology of "zero brush slope (without slope cutting) into the cave, support first and then open the cave." Finally, the microbench excavation method in the cave achieves rapid closure of the primary support structure into a ring, and effectively controls the deformation of the surrounding rock. At the same time, the warming and antifreezing measures such as the warming shed are adopted to, guarantee the construction quality of the concrete of support structure. The above tunnel construction system solves the problem of highhanging tunnel entry construction in plateau area and provides reference for the subsequent construction of similar projects.

Cite this article

WANG Jingang, YU Jingbo, LI Zhijun, LIU Weizheng, CHEN Qiao, ZHOU Guangjie . Construction Technology for Safe Excavation of HighHanging Portal of SichuanTibet Railway Near Primary Class I Water Source[J]. Tunnel Construction, 2021 , 41(S2) : 588 -596 . DOI: 10.3973/j.issn.2096-4498.2021.S2.075

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