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Copyright © 2020 Jing Yang et al. This is an open access article distributed under the Creative Commons Attribution License (the “License”), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License. https://creativecommons.org/licenses/by/4.0/

Abstract

The rock mass failure induced by high in-situ stresses during the excavation of deep diversion tunnels is one of the key problems in the construction of the Jinping II Hydropower Station. Based on the results of acoustic wave tests and rockburst statistical analysis conducted, this study focuses on the excavation damaged zone (EDZ) and rockburst events in the Jinping II diversion tunnels excavated using the tunnel boring machine (TBM) method and the drilling-blasting method. The unloading failure mechanism and the rockburst induced by the two different excavation methods were compared and analyzed. The results indicate that, due to the different stress adjustment processes, the degree of damage to the surrounding rock mass excavated using the drilling-blasting method was more serious than that using the TBM method. The EDZ induced by the TBM was usually distributed evenly along the edge of the excavation surface. While, the drilling-blasting method was more likely to cause stress concentration, resulting in a deeper EDZ in local areas. However, the TBM excavation method can cause other problems in high in-situ stress areas, such as strong rockbursts. The drilling-blasting method is more prone to structural controlled failure of the surrounding rock mass, while the TBM method would induce high stress concentration near the edge of excavation and more widely distributed of stress adjustment induced failure. As a result, the scale and frequency of the rockburst events generated by the TBM were significantly greater than those caused by the drilling-blasting method during the excavation of Jinping II diversion tunnels. The TBM method should be used carefully for tunnel excavation in high in-situ stress areas with burial depths of greater than 2000 m. If it is necessary to use the TBM method after a comprehensive selection, it is suggested that equipment adaptability improvement, advanced prediction, and prediction technology be used.

Details

Title
Comparative Study of the Excavation Damage and Rockburst of the Deeply Buried Jinping II Diversion Tunnels Using a TBM and the Drilling-Blasting Method
Author
Yang, Jing 1 ; Xing-Guo, Yang 2 ; Jia-Wen, Zhou 3   VIAFID ORCID Logo  ; Liu, Yong 4 ; Bao-Shun Dong 5 ; Hai-Bo, Li 2   VIAFID ORCID Logo 

 College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, China; Huaneng Tibet Yarlung Zangbo River Hydropower Development and Investment Co., Ltd., Chengdu 610061, China 
 College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, China 
 State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China 
 Huaneng Tibet Yarlung Zangbo River Hydropower Development and Investment Co., Ltd., Chengdu 610061, China 
 PowerChina Huadong Engineering Co. Ltd., Hangzhou, Zhejiang 311122, China 
Editor
Fengqiang Gong
Publication year
2020
Publication date
2020
Publisher
John Wiley & Sons, Inc.
ISSN
16878086
e-ISSN
16878094
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2474914322
Copyright
Copyright © 2020 Jing Yang et al. This is an open access article distributed under the Creative Commons Attribution License (the “License”), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License. https://creativecommons.org/licenses/by/4.0/