Calculation and Application on Elastic-Plastic Coal Pillar Width of the Stope

Abstract

Abstract Based on the SMP failure criterion which takes into consideration the influence of middle principal stress of clayey stuff, considering stress conditions on gob and roadway, the formula of the coal pillar width is inferred. In the meantime, the plastic-zone width of the coal pillar in plane strain is inferred by use of the limit equilibrium method. Compared with result obtained by Mohr-Coulomb failure criterion by changing the coal internal friction angle and cohesion, it shows that the traditional approach failed to make fully consideration of ultimate strength of the coal, and coal pillar size was designed conservatively. The calculation on coal pillar width based on SMP failure criterion is not only effective, but it will also take an important significance in the secure and efficient production of the coal mine.