Study On Pick Wear Of Coal Auger For Protective Seam Mining

Protective seam mining is the most effective and economic measure to prevent thecoal and gas outburst. The coal seams chosen as the protective seam are thin or ultra-thincoal seams, the seams’ hardness is high and mainly mined used the coal auger.Pickax-shape pick as the cutting tool in mining protective seams, its working life andperformance influence the efficient and cost in mining protective seam. To solve theproblems that cause the pickax-shape picks wear failure in mining protective seam, thearticle analyzes established angle’s influence of ribbed slab picks on coal auger to pickswear and cutting resistance in order to get the established angle that can satisfy the cuttingrequirements and reduce picks wear failure effectively.According to mechanical balance principle, the mechanical models of sharp picks andwear picks are established and the relationship between established angle and mechanicalmodel is got. To avoid the interference of the picks’ body and the coal, the influence ofcutting angle and rotation angle to cutting is analyzed. The equation of U43KL/C22pick’scontour line and coal kerf is established and got the established angle that let picks’ bodyand the coal couldn’t intervene with each other. The study provides theoretical foundationto analyze the picks wear of coal auger.The article analyzes the structure characteristics of the protective coal seam, thephysical mechanical property of coal according to the chosen standard of protective seamand the picks wear failures’ influence. The pickax-shape picks wear is split into hard alloywear and pick body wear. The simplified model of abrasive wear is established on thefoundation of wear theory to find the element than influent picks wear. The abrasive wearof coal is analyzed.Through the introduction of finite element software ANSYS/LS-DYNA and discreteelement software PFC3D, the finite element cutting model of coal auger pick cuttingprotective seam is established. The cutting process of picks with16different established angleare simulated by using finite element software ANSYS/LS-DYNA. The loading conditions ofpicks are obtained. The discrete element cutting model of single coal auger pick is establishedbased on the discrete element uniaxial-compression experiment of coal and rock. The cuttingprocess of picks with16different established angle are simulated by using discrete softwarePFC3D. The loading conditions of picks’surface are obtained.The cutting drill with single pick is designed based on the cutting test bed. To cutdown the test time and the consumption of test coal wall, the picks are produced using low hardness materials to replace the materials of hard alloy and picks body, named assimulation test picks. The average stress-strain curves of coal test specimen with differentproportion are obtained. The test coal wall’s compressive strength is calculated accordingto the designed drill and natural coal’s compressive strength. The test coal istrial-manufactured. The single picks cutting test is conducted using the simulation testpicks, and got picks wear situation with different established angle. The study hastheoretical significance and practical value to confirm the reasonable angle of coal angerand enhance picks wear resistance.