Identification of potential high-stress hazards in deep-buried hard rock tunnel based on microseismic information: a cas
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ORIGINAL PAPER
Identification of potential high-stress hazards in deep-buried hard rock tunnel based on microseismic information: a case study Wen-jing Niu 1 & Xia-Ting Feng 1 & Ya-xun Xiao 2 & Guang-liang Feng 2 & Zhi-bin Yao 1 & Lei Hu 1 Received: 24 March 2020 / Accepted: 12 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Rockbursts, stress-induced collapse, and spalling often occur in the excavation process of deep-buried hard rock tunnel, which affect the stability thereof. The early identification of these potential high-stress hazards during tunnel excavation can provide reliable basis for the selection of preservative and controlled measures. During the excavation of a deep-buried hard rock tunnel in southwest China (a railway tunnel with a maximum burial depth over 2000 m), rockbursts, stress-induced collapse, spalling, and cracking occurred frequently. In this study, the microseismicity of various high-stress hazards in the genesis process of the tunnel was analysed. The difference of microseismicity characteristics of these high-stress hazards was revealed. A matter-element extension mathematical model was established to quantify the microseismicity of the rock mass during tunnel excavation. Based on microseismic (MS) information, an identification method of potential high-stress hazards in deep-buried hard rock tunnels was established. The method was then applied to a real case, and reliability analysis thereof performed. Thirty test case samples were selected for reliability analysis and case verification. Through practical application, it is found that 90% samples were identified correctly. The results show that the identification method of potential high-stress hazards in the deep hard rock tunnel constructed in this study is both applicable and reliable, and can identify potential high-stress hazard types in the process of tunnel excavation by using MS information. Keywords Deep-buried tunnel . Hard rock . High-stress hazards . Microseismic monitoring
Introduction In a high ground stress environment, excavation may cause redistribution of stress, which can lead to unexpected failures. Especially in deep-buried hard rock tunnels, the high-stress feature is notable, and hence, during their excavation, several high-stress hazards, including rockbursts, stress-induced collapse, and spalling are encountered (Kaiser et al. 2004). Different types of high-stress hazards induce different degrees of damage to tunnels, and their various supporting measures and control methods. Even if the rockburst of different
* Xia-Ting Feng [email protected] 1
Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, Northeastern University, Shenyang 110819, People’s Republic of China
2
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, People’s Republic of China
intensity, or the severe spalling and the ordinary spalling or cracking, the safety control measure
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