Stress Zoning Characteristics of Goaf Side and Quantitative Evaluation of Surrounding Rock Stability

Abstract

Aiming to maintain the stability of the mining roadway and the next working-face roadway in the goaf side of a coal mine, a systematic study was carried out, through theoretical analysis, numerical simulation, field case analysis, and other methods, of the synergistic change mechanism in the stress distribution and plastic zone development morphology of the roadway’s surrounding rock in the goaf side under mining disturbance. It was revealed that, under the influence of mining, the goaf side will form a high-deviatoric-stress environment, which directly affects the shape and stability of the plastic zone of the roadway’s surrounding rock. Based on the characteristics of the principal stress ratio and the morphological development law of the plastic zone of the surrounding rock, the side of the goaf is divided into four regions: unloading zone, high-deviatoric-stress zone, low-deviatoric-stress zone, and original-stress zone. And the corresponding mine pressure behavior zoning is proposed: fracture zone, butterfly failure zone, elliptical failure zone, and circular failure zone. A quantitative evaluation method for the stability of the roadway surrounding rock based on the plastic zone morphology criterion was established, and combined with the division of mine pressure, the stability of the surrounding rock on the side of the goaf was quantitatively evaluated.