MMIJ Annual Meeting

Roadways at Kushiro Colliery, where room-and-pillar mining is adopted, experience significant and unpredictable long-term deformations that hinder normal mining operations. To support maintenance planning by forecasting such deformations, this study proposes a novel prediction method that combines elastoplastic stress analysis with in-situ parameter calibration. The elastoplastic analysis is performed using a three-dimensional Displacement Discontinuity Method (3D DDM), enhanced by a newly implemented elastoplastic scheme and consideration of coal creep failure. Parameter calibration was conducted based on monitoring data from an adjacent site to ensure field relevance. The calibrated model was then applied to the target mining site, showing strong agreement between simulation results and field observations. Additionally, a potential mitigation strategy—accelerating dehydration of the backfilling material—is proposed to reduce deformation. The method provides a robust and practical framework for predicting and managing roadway deformations, thereby improving safety and operational efficiency in underground coal mining.