Study on damage of coal seam roof by stress potential function of stacked beam containing frictional action

Abstract

In order to study the damage form and mechanism of coal mine roof, the stress distribution state in the stacked beam model was analyzed by using the stacked beam model and introducing the stress potential function; the model was simplified by using horizontal and vertical joints all over, and the damage range of coal seam roof was analyzed by combining Mohr-Coulomb strength criterion. The results show that the main factors of coal seam roof damage are layer separation caused by horizontal joints and fractures caused by vertical joints; the separation failure zone has a “hyperbolic-like” distribution with steep top and flat bottom, and the fracture damage zone has an “arch-shaped” distribution; with the increase of inter-bed friction coefficient with the increase of the interlayer friction coefficient, the height and width of the layer separation damage zone of the top plate decrease significantly, while the increase of the elastic modulus has less effect on the damage range of the top plate; meanwhile, with the increase of the indirect roof, the fracture height of the top plate gradually decreases and the layer separation width gradually increases.

Keywords

• roof damage
• stacked beam model
• stacked beam stress potential function
• stress distribution
• damage parameter