Study on Failure Mechanism of Interval Coal Pillar in Withdrawal Channel of Large Mining Height Working Face

To solve the problems of poor stability and serious asymmetrical deformation in equipment withdrawal channel at the 2301 face with large mining height, it is necessary to carry out a systematic study on the failure mechanism of the key bearing part, the interval pillar. The pillar width effect of supporting stress and plastic zone distribution law in the pillar was analyzed by means of numerical simulation, theoretical mechanics analysis and mathematical modeling. By establishing the structural mechanics model of “pillar-roof”, the differential equation of coal pillar catastrophe is established and analyzed based on cusp catastrophe theory. Furthermore, the critical catastrophe width of the 2301 working face coal pillar is calculated to be 4.1 m, and the numerical simulation results are consistent with the theoretical calculation results. Therefore, the minimum width of interval pillar should be greater than 4.1 m.