Research on creep damage mechanism and reinforcement measures of water-soaked strip coal pillars

The water-soaked strip coal pillar is subjected to water erosion softening caused by goaf water accumulation during long-term bearing process, which easily leads to varying degrees of damage and deterioration, exacerbating the creep failure of the coal pillar. To further investigate the long-term stability of water-soaked strip coal pillars, this article uses existing constitutive models and OpenGeoSys software to simulate and analyze the creep damage process of water-soaked strip coal pillars under multiple factors. The creep damage mechanism of water-soaked strip coal pillars is analyzed, and a targeted reinforcement method for water-soaked strip coal pillars is proposed. The research results indicate that: (1)the strip coal pillar is in a state of stress concentration for a long time, and under the softening effect of water erosion, the width of the plastic zone of the coal pillar gradually increases, and the degree of damage continues to intensify; (2)the creep damage of coal pillars exhibits a continuous expansion characteristic, with increased inclination angle, burial depth, coal thickness, goaf width, and decreased creep strength all accelerating damage expansion by intensifying stress concentration or expanding the stress concentration range; (3)the proposed concrete grouting and long anchor cable collaborative reinforcement technology can slow down or prevent the creep damage and expansion of coal pillars, and effectively enhance the stability of strip coal pillars.