Experimental study on failure mechanism of soft rock-coal bodies in abandoned mines under cyclic dynamic loading  

作　　者：Dong Wang Yujing Jiang Bin Liang Zhijie Wen Jianlong Wang 

机构地区：[1]State Key Laboratory of Mining Disaster Prevention and Control Co–Founded by Shandong Province and the Ministry of Science and Technology,Shandong University of Science and Technology,Qingdao,266590,China [2]State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology(Beijing),Beijing,100083,China [3]Guizhou University,Guiyang,550525,China

出　　处：《Rock Mechanics Bulletin》2024年第4期41-57,共17页岩石力学通报（英文）

基　　金：supported by the National Natural Science Foundation of China(No.52204101);the Natural Science Foundation of Shandong Province(No.ZR2022QE137);Open Project of State Key Laboratory for Geomechanics and Deep Underground Engineering in CUMTB(No.SKLGDUEK2023);the note(No.YDZX2022141)are gratefully acknowledged.

摘　　要：During the construction and operation of a pumped storage power station in an abandoned mine,the soft rockcoal body structure,comprising the roof and the residual coal pillars,encounters a complex stress environment characterized by cyclic loads.The study of its failure mechanism under cyclic dynamic loading holds significant theoretical and practical importance to stay the safety and stability of the abandoned mine pumped storage power station.In this paper,we take“roof-residual coal pillar”soft rock-coal combinations with different percentages of rock as the research object,and study their mechanical properties,failure mechanism,energy evolution characteristics and acoustic emission distribution characteristics through cyclic dynamic loading experiments.The results of the experiment indicate that:(1)Both weak cyclic dynamic loading and high rock percentage enhance the deformation resistance of soft rock-coal combinations.Under low-disturbance horizontal cyclic loading,its peak strength and modulus of elasticity increase with increasing rock percentage.(2)Under low-disturbance horizontal cyclic loading,an increasing trend is observed in the average total strain energy density,dissipation energy density,and elastic energy density of the combinations as the percentage of rock increases.(3)Under lowdisturbance horizontal cyclic loading,as the percentage of rock increases in the soft rock-coal combinations,the degree of failure in the rock body part progressively intensifies,while the destruction of the coal portion progressively decreases.(4)The large number of acoustic emission signals are generated at the instant of destabilization and destruction of the coal-rock combinations,mainly dominated by the signals generated by the destruction of the coal body.Acoustic emission counts and absolute energy at key point N2 decrease as the percentage of rock increases.The b value is primarily distributed in the cyclic dynamic loading stage and the failure stage,both displaying zones of sudden increase and sudden decreas

关 键 词：Soft rock-coal combinations Energy evolution Failure mechanism Cyclic dynamic loading Acoustic emission 

分 类 号：TD821[矿业工程—煤矿开采] TD31[矿业工程—矿山开采]