NUMERICAL MODELING OF LONGWALL CROSSING OF INCLINED TECHNOLOGICAL CROSSCUTS WITH OVERMINED GATEROADS IN COAL SEAM MINING

Abstract. The paper addresses the problem of assessing the stress-strain state of a geomechanical system during longwall face crossing of inclined technological crosscuts and bunkers connected with overmined gateroads under coal seam mining conditions. The object of the study was the junctions of inclined technological cross-cuts and bunkers of the Southern Panel Belt Roadway with the main longwall face at the 593 m level of seam d4 in the Central Block of the Pokrovske Mine Field. The aim of the research was to determine the stress redistribution patterns in the rock mass and to evaluate the minimum required thickness of the rock plug ensuring safe longwall crossing of the considered junctions. The study was performed using the finite element method in a three-dimensional formulation in the ANSYS Workbench environment. The numerical models accounted for the lithological structure of the rock mass, physico-mechanical properties of rocks, and the Geological Strength Index (GSI). The analysis included von Mises equivalent stresses as well as normal and shear stresses within the rock plug and surrounding rock mass. The results showed that inclined technological crosscuts lead to local stress concentration zones at the junction. For the models corresponding to sections 1-1 and 4-4, potentially hazardous conditions were identified at rock plug thicknesses of 1.2 m and 1.0 m, respectively. An increase in rock plug thickness reduced equivalent stresses and improved rock mass stability. Simulations for sections 3-3 and 5-5 confirmed that a typical rock plug thickness of 3.0 m is sufficient to ensure safe longwall crossing of the considered junctions.

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