Experimental study on the effect of unloading rate on gneiss rockburst
作者机构：State Key Laboratory for Tunnel EngineeringChina University of Mining and TechnologyBeijing100083China Key Laboratory of Active Tectonics and Geological SafetyMinistry of Natural ResourcesInstitute of GeomechanicsChinese Academy of Geological SciencesBeijing100081China School of Mechanics and Civil EngineeringChina University of Mining and TechnologyBeijing100083China
出 版 物：《Journal of Rock Mechanics and Geotechnical Engineering》 (岩石力学与岩土工程学报（英文版）)
年 卷 期：2024年第16卷第6期
页 面：2064-2076页
核心收录：
学科分类：08[工学] 080104[工学-工程力学] 0815[工学-水利工程] 0801[工学-力学（可授工学、理学学位）]
基 金：The financial support from the National Natural Science Foundation of China(Grant Nos.41941018 and 52074299) the Fundamental Research Funds for the Central Universities of China(Grant No.2023JCCXSB02)
主 题：Rockburst Unloading rate Crack propagation Influence mechanisms
摘 要：Rockburst are often encountered in tunnel construction due to the complex geological *** study the influence of unloading rate on rockburst,gneiss rockburst experiments were conducted under three groups of unloading rates.A high-speed photography system and acoustic emission(AE)system were used to monitor the entire process of rockburst process in *** results show that the intensity of gneiss rockburst decreases with decrease of unloading rate,which is manifested as the reduction of AE energy and fragments ejection *** mechanisms are proposed to explain this effect:(i)The reduction of unloading rate changes the crack propagation mechanism in the process of *** makes the rockbursts change from the tensile failure mechanism at high unloading rate to the tension-shear mixed failure mechanism at low unloading rate,and more energy released in the form of shear crack ***,less strain energy is converted into kinetic energy of fragments ejection.(ii)Less plate cracking degree of gneiss has taken shape due to decrease of unloading rate,resulting in the destruction of rockburst incubation *** enlightenments of reducing the unloading rate for the project are also described *** rockburst magnitude is reduced from the medium magnitude at the unloading rate of 0.1 MPa/s to the slight magnitude at the unloading rate of 0.025 MPa/s,which was judged by the ejection velocity.
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