185 / 2023-08-31 22:27:20

Strata Movement Characteristics and Failure Mechanism under Deep Coal Mining in Western China

deep mining,weakly cemented overburden,strata movement,mining subsidence,timoshenko beam,similar material simulation

The sudden strata breakage and dramatic ground subsidence under deep coal mining conditions are urgent issues currently being addressed in coal mining countries around the world. This study investigates the strata movement characteristics and failure mechanism under deep coal mining in western China. Based on the similar material simulation experiment, the failure height of overburden under the mining scale of 0.41,0.81 and 1.21 width-depth ratio are 106 m, 168 m and 181 m respectively. The fracture angle of overburden rock is in the range of 57.7 ° ~ 64.9 °. For the first time, the deep beam theory was applied to the analysis of the overall strata failure in deep coal mining. The theoretical analysis shows that the corresponding width-depth ratio range is 1.22 to 1.34 when the whole strata are completely destroyed, which is consistent with the results of the simulation experiments. Moreover, the breakage of the high-level giant thick weakly cemented overburden belongs to the new damage mode of tensile-shear superposition failure, which is dominated by shear failure. This study offers an important reference for solving the issues related to coal resource safety production and surface ecological protection under deep mining conditions.