A model based on explosive stress wave and tectonic coal zone which gestate dangerous state of coal and gas outburst

Abstract

In terms of the current state of widespread and serious coal and gas outburst problem in south China, by combining widespread tectonic coal, complex geological structure and the process of blast mining and driving used in most ofthe mines, a model based on tectonic coal and explosive stress wave which gestate the dangerous state of coal and gas outburst was proposed and was theoretically analyzed. Study shows that the sparse wave formed by explosive stress wave would lead to coal's density decrease and volume expansion, coal seam gas pressure decrease, coal seam methane adsorption unbalance, and the desorption methane which converted from adsorption methane finally leads to the rise of coal seam gas pressure. When there are tectonic coal zone inthe front of drivageface, the explosive stress wave from explosion source located in drivageface propagates to the interface between no-destruction coal and tectonic coal zone. Due to the strengthened effect of the reflection wave, no-destruction coal which located between tectonic coal and drivageface generates tensile failure. When there are stress concentrated zones inthe front of the drivageface, coal mass would not generate tensile failure like above. With the periodic blasting and driving towardthe tectonic coal zone, the destruction and methane desorption effects on coal mass is constantly strengthened. The strength of explosive stress wave constantly decreases with the increase of distance from explosion source. Finally, the process generates a blastingaccumulation effect.