Stress distribution and surrounding rock control of mining near to the overlying coal pillar in the working face

Abstract

The occurrence of overlying coal pillar (OCP) exerts a strong effect on the stress and strain distribution of the surrounding rock in the stope. In this paper, the stress distribution characteristics are analyzed via the numerical calculation with the account of OCP presence or absence. In addition, this study revealed the joint effect of side pressure relief area of the goaf and stress concentration in OCP on the final stress distribution. Furthermore, the rules of abutment stress distribution affected by three influencing factors, namely horizontal-vertical distances between OCP and working face and buried depth of OCP, are analyzed. The functional model linking the peak stress of surrounding rock with the above influencing factors is developed. The field application of the above results proved that the rib spalling and deformation of a 2.95 m-high and 5.66 m-wide roadway could be efficiently controlled by rationally adjusting working states of the support, and adopting the hydraulic prop coordinated with the π type metal beam and anchor cable to strengthen the surrounding rock of working face and roadway, respectively. The proposed measures are considered appropriate to satisfy the safe operation requirements.