Research on the Deformation Law and Stress Distribution Characteristics of Overburden under the Influence of Multiple Faults

Abstract

Taking the geological conditions of a coal mine in Liupanshui City, Guizhou Province, as the background. The fracture law of the roof in the coal face and the height of the “Two zones” were obtained through theoretical analysis and empirical formula calculation, and the results were verified using similar simulation experiments. Through numerical simulation were researched the stress distribution characteristics of the overlying strata on the working face under the influence of multiple faults. The results showed that in the early stage of mining, F1 undergoes activation under the influence of the main roof weighting, leading to an increase in the degree of plastic damage to the coal seam and strata behind the working face, causing a redistribution of the behind abutment pressure. Finally, under the influence of the F1 barrier effect, the vast majority of the behind abutment pressure is transferred to the lower strata of F1, leading to a continuous increase in stress concentration there. But as the working face continues to advance, the blocking effect of the roof plastic zone above the goaf on the transmission of the behind abutment pressure of the working face begins to appear and continues to increase, leading to a decrease in the peak stress at the lower strata of F1. The stress change process on the F2 side is similar to that on the F1 side, the front abutment pressure is initially distributed in the strata in front of the working face, but as the activation degree of F2 continues to intensify, it gradually shifts to the lower strata of F2, and ultimately the majority of the front abutment pressure is borne by the lower strata of F2.

Mechanism of Stratum Instability and Dynamic Deformation under Discontinuous Boundary Conditions

“…Zhu et al [21,22] studied the mechanical characteristics of fractured surrounding rock in damaged tunnels and analyzed the mechanical deformation and failure characteristics of fractured surrounding rock through rock mechanics experiments. Yu et al [23,24] carried out three-dimensional geological modeling of a quarry containing close-range double faults based on the site, and through similar simulation experiments and three-dimensional numerical simulation analysis, they derived the form of mutual transformation of the energy and stress of the two faults in the whole mining process of the quarry, the overall joint control mechanism of the faults on the regional peripheral rock structure, and the law of the mutual influence of the faults, and, moreover, they gave a map of the joint action of the two faults in the whole mining process. Wu et al [25] analyzed the occurrence mechanism of impact ground pressure in the graben tectonic zone formed by two faults by establishing mechanical models and numerical simulations.…”