DIC-based similar simulation study on the evolution patterns of mining-induced fracture, displacement and strain in close distance coal seam

Abstract

This study investigates the fracture evolution patterns of overlying strata under the mining conditions of close-distance coal seams.Taking the 9305 working face of Anshun Coal Mine as the research object, this study probed into the evolution of displacement field and strain field during the mining process of close-distance coal seams through physical similarity simulation test.The results show that ①with the continuous advancement of distance from the working face, the overburden strata first form separation cracks and longitudinal cracks, and then the middle part of the goaf is gradually compacted.②The displacement field is asymmetrically distributed in the advancing direction of the working face, The displacement of the overlying rock on the side of the working face is obviously smaller than that on the left side of the goaf, and the peak displacement is mainly concentrated in the middle of the goaf.③The maximum principal strain concentration position is asymmetrically transferred from the middle of the goaf to the open-off cut side and the working face side.The concentration degree of the open-off cut side is significantly higher than that of the working face side.This reveals that a potential correlation exists between the maximum principal strain concentration position and the gas enrichment area.

Keywords

• close distance coal seam
• overburden rock structure
• fissure evolution
• displacement strain
• similar simulation