Numerical simulation about the mine pressure law with sub-level caving mining of large section roadways along gob in extremely thick coal seam

Purpose to control the mine pressure law with sub-level caving mining of large section roadways along gob in extremely thick coal seam,reproduces the whole process of coal mining by numerical simulation based on 5203 roadway in Tashan Coal Mine,and monitored the law of rock displacement,axial force and rock anchor bolt stress,etc. The results showed that: the influence on strata of mining has no effect stages,micro-impact stages and high-impact stages,the distances from the face were more than 120m,120 ~ 50m and less than 50m; the axial force of anchor gradually increased with the face of approaching,but the axial force decreased rapidly when the distance is less than 14m away from the face,and the effect of mining on cables near coal pillar is larger than others; effective supporting limit the destruction of roadway excavation rock,and the stress concentration around the tunnel reaches 17MPa; coal is damaged under the enormous lead abutment pressure and its internal stress is released after coal mining,so coal or coal pillar have multiple stress peaks.