Experimental study on progressive failure characteristics of strip coal pillar models under different roof and floor conditions

Abstract

To study mechanical properties and progressive failure characteristics of strip coal pillar, a progressive failure monitoring device was developed. The uniaxial compression test of “roof-strip coal pillar-floor” structure specimens were conducted. As the strength of the roof and floor increases, the strength of structural specimen increases. The damage of the strip coal pillar from middle to the coal-rock interface, and the lateral displacement of the upper part is larger than the lower part. Energy accumulation and release cause discontinuity damage in inhomogeneous coal bodies, the lateral displacement of the strip coal pillar shows step and mutation characteristics. Under hard surrounding rocks, the brittleness and impact characteristics of strip coal pillar are more obvious. The rapid increase of acoustic emission signal can be a failure precursory of strip coal pillar. The research has theoretical value and practical engineering significance to understanding the stability and failure mechanism for strip coal pillar.

Keywords

• Rock mechanics
• “Roof-strip coal pillar-floor” structure
• Progressive failure characteristics
• Acoustic emission
• Strip coal mining