Coupling model of disk splitting for expansive rock mass in deep storage considering water infiltration

Abstract

AbstractEnergy storage in deep underground and mineral mining has currently become a hot research topic. To investigate the tensile failure of expansive soft rocks, a disk splitting mechanical model was established under a coupled action of the humidity and mechanical fields. Then, based on the theory of humidity stress field and the solution to the stress of a semi‐infinite body under the action of a concentrated force, an analytical formula for the stress of the disk under the action of the two fields was derived. Using the analytical formula, the influence of the humidity field and disk physical parameters on the distribution of the stress field on the disk under the coupled humidity‐mechanical action was further analyzed. Finally, the formula for the splitting tensile strength of expansive soft rocks under the influence of humidity was modified. The analysis results showed that the stress evolution of the disk under the coupled humidity‐mechanical action was completely different from that under a single‐load action. The stress concentration was generated at the dry‐wet interface of the disk. In addition, the range and value of the stress concentration zone increased with the increase in the humidity of the external environment, elastic modulus of soft rock, and linear expansion coefficient. Under the action of a single load, the cracking position was at the center of the disk. In contrast, under the coupled humidity‐mechanical action, the cracking position was transferred to the intersection of the dry‐wet interface and the loading direction. The above results can provide preliminary theoretical guidance for understanding the tensile failure mechanism of expansive soft rocks.