| Popis: |
The stress of rock strata changes under mining action, and the arch structure will be formed around the mining area. The stability study of the arch structure has crucial scientific value for solving the problems of stope pressure and surface subsidence. In this paper, the development process of rock strata arch structure is studied by theoretical analysis and particle flow numerical simulation, and the stability of the arch structure is analyzed. At the same time, based on the rock strata breaking theory, the calculation formulas of the development height and the critical width of the instability of the arch structure are obtained, and the correctness of the formula is verified by numerical simulation. The results show that during the mining stage of the working face, the rock strata arch structure has experienced the process of arching-arch breaking, and the instability of the arch structure is the root cause of increasing surface subsidence damage. The arch structure development height h is the sum of rock strata breaking height Hi and unbroken rock strata arch development height Hig. The theoretical calculation shows that when the width:depth ratio of the working face is 1.60, the height of the arch structure exceeds the bedrock top, which is consistent with the numerical simulation results and verifies the correctness of the formula. By defining the instability coefficient C of rock strata arch structure, a method to judge the stability of the arch structure is provided. The theoretical calculation shows that the critical width L0 of the arch structure instability is 134 m, which is not much different from the numerical simulation results of 136 m, and the correctness of the formula is proved. The research results have particular reference value for preventing ground disasters caused by underground coal mining and controlling ground subsidence and provide a reference for the application of the particle flow method in studying rock strata movement. |
