Numerical Simulation On The Deformation And Damage Of Coal-rock And The Damage Of Interface In Mining Process

In order to improve the effectiveness, security and economy of coal-mining, by numerical simulating the deformation and damage effecting of coal seam and the upper rock interface under the disturbance load, reaching the failure mechanism of coal layer and rock and interface system, to made the foundation for the disaster of sulfide gas and gas outburst mechanismIn this paper using ABAQUS to simulate the mining process. Using Drucker-Prager and Traction Separate Law as the yield criterion and the damage criterion.Numerical results indicate as follows:(1) with the angle increases, the maximum and minimum principal stress values were located in the lower left bottom of mined area and the top right of the roof and in the distribution it is obviously different with the horizontal seam; the concentration zones of vertical stress which the stress increases transfer and expand continually to the lower floor; the bottom shear stress is growing between the upper roof and the lower bottom side in front of work place and it spread gradually forward higher stress concentration zone.(2) Along the coal seam mined-out area the roof deformation shows curved sinking characteristics and it seems like asymmetrical skewed funnel. Around the top right end of the roof and near the exploitation of coal have a larger horizontal displacement; the bigger the slop angles, the bigger the vertical displacement.(3) Under the disturbance loads, the stiffness of interface decreased and even failed in the exploitation process, with the damage of interface expanded, leading to generate the fracture and defects around the mined out space.(4) Near the work place slope coal seam obtained greater tensile stress, the crack group growth rapidly, so that coal damage and even failure, the bigger the slop angles, the earlier the damage appeared.