Deformation and failure mechanism of roadway in open-pit end slope mining

Abstract

In order to study the deformation and failure mechanism of the roof in end slope mining, a mechanical model of the two-end fixed beam was established, combined with the theory of elasticity to derive the calculation equations for the stress and displacement of the roof, and to consider the effect of the extrusion of the overlying weak rock layer of the rib pillar on the deformation of the roof, and finally, the analysis obtained the stress distribution and deformation law of the roof. The research shows that the distribution of normal stresses in the roof is parabolic with a secondary axisymmetric distribution at the center of the roadway, and the maximum tensile stress is at the center of the bottom of the roadway. The maximum tensile stress and the maximum shear stress on the roof increase continuously with the increase of mining progress. The location of the middle of the bottom surface of the roof first shows tensile failure, and then gradually changes to shear failure at the contact location with the coal pillars. The value of u at the bottom of the roof rock beam shows a trend of first decreasing, then increasing, and finally decreasing as x increases, but lateral extrusion has little effect on the horizontal displacement of the roof. The displacement component ν of the roof shows a parabolic variation law with x opening upward. The absolute value of displacement |ν| considering the simultaneous action of vertical compression and lateral extrusion is the most obvious.

Keywords

• end-slope mining
• roof deformation of mining chamber
• failure mechanism
• mechanical model
• stress distribution
• extrusion deformation