Abstract:
When mining the lower coal seam in shallow?buried close?distance coal seams passing through overlying residual coal pillars, strong ground pressure disasters characterized by roof step subsidence or support crushing are frequently induced. Quantitative risk assessment of such disasters remains a bottleneck for on?site control. Taking the Shendong mining area as the engineering background, a combined method integrating roof structure theoretical analysis and analytic hierarchy process (AHP) weighted summation method, supplemented by fuzzy comprehensive evaluation as an auxiliary approach, was employed to systematically investigate the main controlling factors and quantitative risk assessment methodology of strong ground pressure during coal pillar crossing. Based on the mechanical chain model of “coal pillar static load source – overburden load transfer medium – mining response”, nine key indices were identified, including inter?mining ratio, angle between coal pillar and working face, stability of interburden strata, etc. A three?level hierarchical evaluation system was established, and a four?grade quantitative classification standard (weak, general, moderate, high) was developed for each index. The composite weights of indices were calculated by AHP, and a comprehensive risk index R together with a four?level risk classification standard was proposed. The applicability of the weighted summation method and the fuzzy comprehensive evaluation method was compared, and the weighted summation method is recommended as the primary model. This system achieves a leap from single empirical judgment to multi?factor quantitative comprehensive assessment, providing a scientific basis for risk assessment and management of through coal pillar mining.