Podkopayev Y. Justification of the methods of maintaining the stability of rollback stretches in the development of steep coal seams

The dissertation solves the actual scientific and technical task of substantiating the methods of maintaining the stability of rollback stretches during the development of steep coal seams on the basis of the disclosure of natural features and laws of geomechanical processes that manifest themselves in the coal massif and their influence on the deformation properties of protective structures due to the change in the specific potential energy of deformation, when when managing the state of the roof, their shape and volume are transformed with a simultaneous increase in rigidity without loss of stability, due to which the convergence of side rocks on the contour of the preparatory works is limited and their operational condition is ensured along the length of the excavation section. The idea of the work was to use the natural features and regularities of geomechanical processes, which are manifested in the coal massif during its unloading and taking into account the deformation properties of the protection structures, contribute to the preservation of the integrity of the side rocks and the stability of the roll-back lines in the excavation sections of deep coal mines with steep strata. The purpose of the work was to substantiate the methods of maintaining the stability of the roll-back lines, which ensure their operational condition at excavation sites in deep coal mines with steep strata. The following tasks were set and solved in the work: an analysis of studies of the stability of preparatory works was carried out, taking into account the methods of protection to solve the task of effective and safe coal mining in mines with steep strata; i icono-analytical and laboratory studies of the stability of side rocks in the coal-bearing massif to substantiate the methods of protection of roll-back stretches that ensure their operational condition; the influence of the deformation properties of protective structures of preparatory workings on the condition of side rocks in the coal-bearing massif to ensure the stability of the roll-back stretches of steep formations has been determined; full-scale studies of the stability of roll-back lines with different protection methods were carried out at the excavation sites of the coal mine to substantiate the protection methods that ensure the operational condition of the workings; developed solutions that allow forecasting the state of preparatory workings of steep layers and methods of protection of roll-back stretches, which are aimed at preserving their stability along the length of the excavation section in deep coal mines. The object of the research is the processes of managing the state of the roof in the coal-bearing massif to ensure the stability of the rollback stretches of steep formations. The subject of the study was the patterns of changes in the deformation properties of the protective structures of the preparatory workings of steep formations. The work used a comprehensive approach, which included: analysis and generalization of known research; analytical and laboratory studies of deformation properties of protective structures of preparatory works; mine instrumental observations of the process of deformation of side rocks on the contour of rollback stretches and changes in their cross-section with various methods of protection along the length of the excavation section; analysis and interpretation of the obtained results; methods of probability theory and experimental planning. The conducted research formed the basis of the developed technical solutions aimed at preserving the stability of rollback stretches during the development of steep coal seams. Increasing the effectiveness of measures to preserve the rolling tracks in operational condition along the length of the excavation site is ensured by the use of flexible protective structures made of wood, full or partial laying of the created space. In order to preserve the operational condition of roll-back shafts in mines that develop layers of a steep fall, methods of protection of workings are proposed (Ukrainian patents for a utility model u 2020 00142; u 2020 04458; u 2020 02441; u 2021 00893). The results of the research were used in the development of recommendations for ensuring the stability of rollback lines in the mining areas of the coal mines of the State Enterprise «Toretskvugillia». The scientific and practical results of the work were used in the educational process of the State Higher Education Institute «Donetsk National Technical University» and during the teaching of disciplines to students of disciplines « Mechanics of rocks and Massifs», «Protection of mine workings» and «Development of mineral deposits in difficult mining and geological conditions» by students majoring in 184 Mining.