State Key Laboratory of Coal Resources and Safe Mining School of Mines China University of Mining&Technology Xuzhou 221116 China;
State Key Laboratory of Coal Resources and Safe Mining School of Mines China University of Mining&Technology Xuzhou 221116 China;
State Key Laboratory of Coal Resources and Safe Mining School of Mines China University of Mining&Technology Xuzhou 221116 China;
State Key Laboratory of Coal Resources and Safe Mining School of Mines China University of Mining&Technology Xuzhou 221116 China;
State Key Laboratory of Coal Resources and Safe Mining School of Mines China University of Mining&Technology Xuzhou 221116 China;
Loose gangues backfill body; Confined compression; acoustic emission; spacetime evolution; failure mechanism;