A mechanism and characteristic analysis of rock core discing in the in-situ stress survey on deep coalmine

Rock core discing arises in the process of in-situ stress survey on Jiulong mine of Fengfeng mine area when hollow inclusion stress-relief method is applied. At the mean time, the data of the in-situ stress is obtained. By measuring the in-situ stress of this district, this paper analyzes the stress condition and the characteristics of rock core discing when the stress is relieved in the in-situ stress measurement process, and the core coring operation is stimulated by mathematical software. The relationship between the in-situ stress and the rock core discing is figured out by stress analysis of the rock core discing based on the measured geostress data. The result points out that discal drill core is a special outcome of certain stress field. It indicates the stress field level. The position of discal drill core break does not absolutely located at the root of the rock core, and the discal drill core is roughly of uniform thickness. The drill core plate breaks from the surface of the drill core, and the crack size depends on the in-situ stress. This paper discloses the inner link of the in-situ stress and the discal drill core, offering reference for the back analysis of the crustal stress field in light of the characteristics of rock core discing.