Monitoring and evaluation of disaster risk caused by linkage failure and instability of residual coal pillar and rock strata in multi-coal seam mining
Qing Ma, Xiaoli Liu, Xiaoli Liu, Yunliang Tan, Yurui Wang, R. B. Wang, Enzhi Wang, Xuesheng Liu, Xuesheng Liu, Zenghui Zhao, Darui Ren, Weiqiang Xie, Ruipeng Qian, Nan Hu
Abstract
Comprehensive research methods such as literature research, theoretical analysis, numerical simulation and field monitoring were used to analyze the disasters and characteristics caused by the linkage failure and instability of the residual coal pillars-rock strata in multi-seam mining. The effective monitoring area and monitoring design method of linkage instability of residual coal pillar-rock strata in multi-seam mining were determined. The evaluation index and the risk assessment method of disaster risk was established and the project case was applied and verified. The results show that: ①The coal pillar will not only cause disaster in single-seam mining, but also more easily cause disaster in multi-seam mining. The instability of the coal pillar will not only lead to dynamic disasters such as rock burst and mine earthquake, but also cause surface subsidence and other disasters. ②When monitoring the linkage instability of residual coal pillar-rock strata, it is not only necessary to consider the monitoring of the apply load body (key block), the transition body (residual coal pillar) and the carrier body (interlayer rock and working face), but also to strengthen the monitoring of the fracture development height (linkage body). ③According to the principles of objectivity, easy access and quantification, combined with investigation, analysis, and production and geological characteristics of this mining area, the main evaluation indexes of the degree of disaster caused by linkage instability of residual coal pillar-rock strata are determined as: microseismic energy, residual coal pillar damage degree, fracture development height. And the evaluation index classification table was also given. ④According to the measured value of the evaluation index, the fuzzy comprehensive evaluation method was used to calculate the disaster risk degree in the studied mine belongs to class III, that is, medium risk level. The corresponding pressure relief technology was adopted on site, which achieved a good control effect, and also verified the accuracy and effectiveness of the risk evaluation results.