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Geomechanics and Engineering
  Volume 29, Number 2, April25 2022 , pages 99-111
DOI: https://doi.org/10.12989/gae.2022.29.2.099
 


Experimental investigation on bolted rock mass under static-dynamic coupled loading
Pengqi Qiu, Jun Wang, Jianguo Ning, Xinshuai Shi and Shanchao Hu

 
Abstract
    Instability of bolted rock mass has been a major hazard in the underground coal mining industry for decades. Developing effective support guidelines requires understanding of complex bolted rock mass failure mechanisms. In this study, the dynamic failure behavior, mechanical behavior, and energy evolution of a laboratory-scale bolted specimens is studied by conducting laboratory static-dynamic coupled loading tests. The results showed that: (1) Under static-dynamic coupled loading, the stress-strain curve of the bolted rock mass has a significant impact velocity (strain rate) correlation, and the stress-strain curve shows rebound characteristics after the peak; (2) There is a critical strain rate in a rock mass under static-dynamic coupled loading, and it decreases exponentially with increasing pre-static load level. Bolting can significantly improve the critical strain rate of a rock mass; (3) Compared with a no-bolt rock mass, the dissipation energy ratio of the bolted rock mass decreases exponentially with increasing pre-static load level, the ultimate dynamic impact energy and dissipation energy of the bolted rock mass increase significantly, and the increasing index of the ratio of dissipation energy increases linearly with the pre-static load; (4) Based on laboratory testing and on-site microseismic and stress monitoring, a design method is proposed for a roadway bolt support against dynamic load disturbance, which provides guidance for the design of deep underground roadway anchorage supports. The research results provide new ideas for explaining the failure behavior of anchorage supports and adopting reasonable design and construction practices.
 
Key Words
    bolted rock; crack propagation; dissipation energy; dynamic mechanical properties; split Hopkinson pressure bar; static-dynamic coupled loading
 
Address
Pengqi Qiu: College of energy and mining engineering, Shandong University of Science and Technology, 579 Qianwangang Road, Qingdao, China;
College of mining engineering, Taiyuan University of Technology, 18 Xinkuangyuan Road, Taiyuan, China
Jun Wang, Jianguo Ning, Xinshuai Shi and Shanchao Hu: College of energy and mining engineering, Shandong University of Science and Technology, 579 Qianwangang Road, Qingdao, China
 

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