Research on Determination of Coal Pillar Bearing Law and Width Based on Coal Damage Evolution

Abstract

In order to solve the on-site problems of unclear coal pillar bearing law and difficult determination of reasonable width, this paper uses numerical simulation and on-site industrial tests to analyze the wall rock deformation law, coal pillar bearing property evolution law, the law of internal crack propagation and support control of coal pillar. The evolution process and distribution characteristics of internal cracks of coal pillars under the influence of mining on both sides are analyzed, and the damage and failure mechanism of the expansion of the original cracks to the macro-fracture surface under mining stress is revealed, and the damage range on both sides of the coal pillar is determined. Based on the first damage of the coal pillar, the failure mechanism of the internal cracks of the coal pillar from the two sides to the middle after the roadway was excavated, and the distribution characteristics of the shear cracks and the tensile cracks and the pillar load were established. The stability of roadway surrounding rock corresponding to coal pillars different widths are studied, and finally the wind at 7106 face is determined. The reasonable width of the coal pillar of the roadway is 7.0 m; the coal pillar stability support control technology is proposed by using high-strength threaded steel bolts and double-ribbed double-beam reinforced ladder beam support, and using prestressed anchor cable to strengthen the support. Field application practice shows that the support control effect is good.

Keywords

• working face
• coal body damage
• coal pillar stability
• support control
• numerical simulation