Theoretical analysis on the deformation characteristics of coal wall in a longwall top coal caving face

Against the background of analyzing coal wall stability in 14101 fully mechanized longwall top coal caving face in Majialiang coal mine, based on the torque equilibrium of the coal wall, shield support and the roof strata, an elastic mechanics model was established to calculate the stress applied on the coal wall. The displacement method was used to obtain the stress and deformation distributions of the coal wall. This study also researched the influence of support resistance, protective pressure to the coal wall, fracture position of the main roof and mining height on the coal wall deformation. The following conclusions are drawn: (1) The shorter the distance from the longwall face, the greater the vertical compressive stress and horizontal tensile stress borne by the coal wall. The coal wall is prone to failure in the form of compressive-shear and tension; (2) With increasing support resistance, the revolution angle of the main roof decreases linearly. As the support resistance and protective force supplied by the face guard increases, the maximum deformation of the coal wall decreases linearly; (3) As the face approaches the fracture position of the main roof, coal wall horizontal deformation increases significantly, and the coal wall is prone to instability; and (4) The best mining height of 14101 longwall face is 3.0 m.