EVALUATION OF STABILITY OF ROLLING STRAPS OF STEEL COAL LAYERS WITH THE WAY OF PROTECTION BY WOODEN FIRE

Abstract

Purpose. To evaluate the impact of overburden protection structures, in the form of wooden fires, on the stability of lateral rocks in the coal massif and the operational condition of the preparatory workings on the excavation section of the coal mine, which develops layers of steep fall. Methods. An integrated approach was used as a research method, which included conducting a mine experiment, equivalent modeling and interpretation of the obtained results. Results. The stability of retractable drifts on excavation sections was evaluated by the amount of convergence of the side rocks on the production contour, taking into account the deformation characteristics of the protection structures. During the full-scale experiment, when the change in the distance between the benchmarks on the contour of the retractable lane in the area affected by the cleaning works was recorded, the largest displacements of the side rocks were recorded from the roof. At a distance of l≥60 m behind the treatment face, the relative deformation of the protection structures reached ε = 0.5-0.6. After that, the increase in roof displacements was limited, and the superstructure supporting structures operated in the mode of increasing resistance. During laboratory research, in the process of compressing models of wooden fires and rolling fires from sleepers, their deformation characteristics were established. At uniaxial compression of models there was a consolidation of experimental samples. With an increase in the compressive force and relative deformation of the experimental samples, a simultaneous change in the modulus of deformation and stiffness of the simulated security structures by quadratic dependence was recorded. Scientific novelty. It is experimentally proved that in the zone of influence of treatment works the convergence of lateral rocks on the contour of the retractable road of the steep coal seam under protection by wooden fires along the length of the excavation section is limited after compression of security structures by 50-60% due to their compaction. the layout of the elements and their number, determine its rigidity. Practical significance. To ensure the stability of retractable drifts on mines that develop steep fall layers, it is necessary to focus on the use of flexible protective structures located above the drift and performing the function of load-bearing supports, which by changing the deformation characteristics provide smooth deflection of lateral rocks in the coal massif. Keywords: steep fall of coal seams, haulage gate, side rocks, security structure, deformation characteristics, rigidity.