INFLUENCE OF FRACTURE INCIDENCE ANGLE ON THE LOCAL STRESS STATE OF THE NEAR-SLOPE ZONE OF THE OVERBURDEN LEDGE

Relevance. The stress-strain state of the rock massif during open-pit mining of mineral deposits, as well as during construction in excavations of significant size, depends on both the mechanical properties of rocks and the structural and textural features of the rock massif. In particular, the presence of cracks in the near-slope zone of the ledge can significantly weaken its stability, and the direction and angle of crack incidence relative to the ledge slope change the location of stress zones within the massif relative to the surface of the outcrop. The identification of zones of increased mechanical stresses in order to predict the behavior of rock massifs with different structural-textural properties is an urgent scientific and practical task. The main aim is identification of the stress concentration zones in the near-slope part of the ledge in the rock massif with different structural-textural properties during open-pit mining. Methods: mathematical modeling of rock massifs with regard to their physical and mechanical properties and structural and textural features using the finite element method, processing the results of experimental studies. Results. The paper introduces the description of the mathematical model of the elastic behavior of a natural fractured rock massif with an outcrop surface in the form of a ledge, as well as the laws of stress concentration distribution in it. The stress-strain state of loaded and unloaded massifs in the undisturbed and disturbed by cracks of different orientation states is described, and their values for ledges with different structure are compared. The authors have revealed the increased values of tensile stresses in the massif in the direction of crack incidence from the ledge slope compared to the undisturbed state and in the direction of crack incidence toward the ledge slope.