Development of geomechanical model for determination of elastic modulus and study on law of caving span induced by mechanized longwall mining

A geomechanical model is developed to determine the elastic modulus, to analyze the rules of rock and surface displacement, and study the caving span caused by mechanized longwall mining.The rules of rock deformation and displacement have been determined, including the stress distribution, the development of the failure zone, the height of the failure zone, the caving span of the longwall, the order of layer arrangement, the displacement deformation vector, the maximum subsidence, and the boundary displacement angle.In this paper, the author uses the Rocdata program to determine the elastic modulus (E), cohesion (C), and internal friction angle () as inputs for the geomechanical model.The software RS2 (Phase 2) from Rocscience Inc. (Canada) is then used to calculate some parameters and displacement quantities.The results showed that the maximum subsidence in the dip direction is = -2.250m and in the strike direction = -0.659m.The boundary displacement angle is 0 = 47.The caving height is H = 10 m.The caving repeats at the span 10th, meaning that the length of the longwall mined in the strike direction reaches 65 m.Afterward, the caving span and the height of the caving zone repeat.