ON SOME ROCK MASSIF PARAMETERS INFLUENCE ON QUANTITATIVE ESTIMATES OF THE SEAM OPENING ROOF CONDITION

The opening headed through the coal seam roof rock geomechanical condition problem solution results are presented. The bedding rock strength exceeds the seam strength. The diagram of the seam conditional stresses corresponds to the Prandtl diagram, in which the material's ultimate deformation section is parallel to the abscissa axis.In the reviewed boundary value problem, the rock massif operates under conditions of a flat deformed state, and the seam zones located in the walls of the mine opening are in an extremely strained state. The problem is solved by the method of boundary elements using the general strength criterion of Coulomb-Moore strength theory and a special criterion of Moore- Kuznetsov strength theory.Based on the conducted studies results, a graph of the lateral pressure values coefficient is plotted, corresponding to the appearance of tensile stresses in the mine roof, depending on the opening span. The roof rock strength coefficient graphs have also been plotted, depending on the opening span, when vertical fracture cracks appear in the roofs. It is shown that, at some values of the lateral pressure coefficient, the appearance of fracture cracks in the seam roof above the opening occurs earlier than the roof passes into the limiting state due to the forces of the bearing pressure.