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<p>Addressing the problem of intense strata pressure induced by dynamic impact events from overlying room-and-pillar goafs in China’s Shendong mining area, this study took the Guojiawan Coal Mine (GCM) as a case study. By combining similarity experiments, stress superposition principles, and numerical analysis, the response mechanisms of Overlying Residual Room-Pillars (ORRPs) to mining activities and their associated dynamic impact effects were revealed. The results demonstrated that three key factors collectively drive two distinct failure modes in small ORRPs: Destressing Failure above Mined-out Areas (DFMA) and High Stress Instantaneous Failure (HSIF) above the active longwall face. The HSIF mode triggers the dynamic impact events. The influence of each factor on the load state of ORRPs in the high-stress zone was quantified. Furthermore, a calculation method for the dynamic impact force was established. Theoretical calculations determined that the dynamic impact load exerted by the roof on the floor subsequent to HSIF was 34.28&#xa0;MPa/25 m<sup>2</sup>, while Finite Difference Method (FDM) numerical modeling yielded 31.443&#xa0;MPa/25 m<sup>2</sup>, destabilizing the load-bearing structure of the main roof above the longwall face and thereby inducing intense strata pressure. The revealed exponential decay model for the dynamic impact effect indicated that its downward influence extended to at least 60&#xa0;m. Based on these findings, a hydraulic fracturing prevention technique was proposed to pre-fracture the longwall face roof. Field measurements confirmed the effectiveness of this technique, as the maximum hydraulic support pressure reached 40&#xa0;MPa, well below its rated load-bearing capacity. This validates the successful mitigation of dynamic impact hazards, and also proves beneficial for roof caving control.</p>

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Zoned Failure Mechanism and Dynamic Impact Effects of Overlying Residual Room-Pillars

  • 期刊论文

  • 发表日期：

    2026年2月20日

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  • Weidong Pan,
  • Cang Deng,
  • Zhining Zhao,
  • Xiyuan Qin,
  • Yupei Deng,
  • Xianjin Li,
  • Fei Wang

摘要

Addressing the problem of intense strata pressure induced by dynamic impact events from overlying room-and-pillar goafs in China’s Shendong mining area, this study took the Guojiawan Coal Mine (GCM) as a case study. By combining similarity experiments, stress superposition principles, and numerical analysis, the response mechanisms of Overlying Residual Room-Pillars (ORRPs) to mining activities and their associated dynamic impact effects were revealed. The results demonstrated that three key factors collectively drive two distinct failure modes in small ORRPs: Destressing Failure above Mined-out Areas (DFMA) and High Stress Instantaneous Failure (HSIF) above the active longwall face. The HSIF mode triggers the dynamic impact events. The influence of each factor on the load state of ORRPs in the high-stress zone was quantified. Furthermore, a calculation method for the dynamic impact force was established. Theoretical calculations determined that the dynamic impact load exerted by the roof on the floor subsequent to HSIF was 34.28 MPa/25 m2, while Finite Difference Method (FDM) numerical modeling yielded 31.443 MPa/25 m2, destabilizing the load-bearing structure of the main roof above the longwall face and thereby inducing intense strata pressure. The revealed exponential decay model for the dynamic impact effect indicated that its downward influence extended to at least 60 m. Based on these findings, a hydraulic fracturing prevention technique was proposed to pre-fracture the longwall face roof. Field measurements confirmed the effectiveness of this technique, as the maximum hydraulic support pressure reached 40 MPa, well below its rated load-bearing capacity. This validates the successful mitigation of dynamic impact hazards, and also proves beneficial for roof caving control.