Numerical study on micro-fracture mechanism of rock dynamic failureinduced by abrupt unloading under high in-situ stresses  

作　　者：Yuezong Yang Anye Li Zhushan Shao Kui Wu Wei Wei Wenhui Du Yujie Wang 

机构地区：[1]School of Science,Xi’an University of Architecture and Technology,Xi’an 710055,China [2]CAEP Software Center for High Performance Numerical Simulation,Institute of Applied Physics and Computational Mathematics Beijing,Beijing 100088,China

出　　处：《Theoretical & Applied Mechanics Letters》2024年第6期486-495,共10页力学快报(英文版)

基　　金：supported by the National Natural Science Foundation of China(Grant No.12302501);the China Postdoctoral Science Foun-dation(Grant No.2023MD744236);the Natural Science Basic Research Program of Shaanxi(Grant No.2024JC-YBQN-0061);the Postdoctoral Research Project of Shaanxi Province(Grant No.2023BSHEDZZ270);the Special Scientific Research Plan Project of Education Department of Shaanxi Provincial Government(Grant No.23JK0509);the Scientific Research Foundation for Excellent Returned Overseas Chinese Schol-ars funded by Shaanxi Provincial Government(Grant No.2023-021);the Innovation and Entrepreneurship Projects for College Students(Grant No.S202310703047).

摘　　要：Rock burst is a kind of severe engineering disaster resulted from dynamic fracture process of rocks.The macrofailure behaviors of rocks are primarily formed after experiencing the initiation,propagation,and coalescenceof micro-cracks.In this paper,the grain-based discretized virtual internal bond model is employed to investigatethe fracturing process of unloaded rock under high in-situ stresses from the micro-fracture perspective.Thesimulated micro-fracturing process reveals that the longitudinal stress waves induced by unloading lead to thevisible unloading effect.The influences of in-situ stresses,mineral grain sizes,and grain heterogeneity on rockmacro and micro fracture are investigated.Micro-crack areas of tensile and shear cracks and micro-crack anglesare statistically analyzed to reveal the rock micro-fracture characteristics.The simulated results indicate thatthe combined effect of the stress state transition and the unloading effect dominates the rock unloading failure.The vertical and horizontal in-situ stresses determine the stress state of surrounding rock after unloading andthe unloading effect,respectively.As the vertical stress increases,the stress level after unloading is higher,andthe shear failure characteristics become more obvious.As the horizontal stress increases,the unloading effectincreases,leading to the intensification of tensile failure.The mineral grain size and grain heterogeneity alsohave nonnegligible influences on rock unloading failure.The micro-fracture perspective provides further insightinto the unloading failure mechanism of deep rock excavation.

关 键 词：Rock burst MICRO-FRACTURE Dynamic failure Unloading effect 

分 类 号：TG1[金属学及工艺—金属学]