Experimental study on gas explosion induced by caving friction of goaf roof

Abstract

The collision and friction between the rock masses during the caving of the gob roof has become an important hidden danger to induce the gas explosion accident in the gob. In order to study the mechanism of gas explosion induced by sandstone friction by friction velocity, friction force, gas concentration, SiO2 content and other factors, the rock friction effect igniting gas test system was used to conduct quantitative test research on each factor. The results show that when the gas concentration is 7.0%-11.5%, the gas explosion time induced by sandstone friction first decreases and then increases with the increase of gas concentration. The high friction and hot surface of sandstone is the main cause of gas explosion. Gas explosion induced by friction can be divided into two stages: gas burning on sandstone friction surface and gas explosion diffusion. The time of gas explosion induced by friction decreases with the increase of friction and the increase of SiO2 content in sandstone. When the friction is lower than the minimum critical velocity, the gas explosion will not be induced. When the friction is higher than the minimum critical velocity and lower than the maximum critical velocity, the maximum friction velocity is negatively correlated with the gas explosion time.

Keywords

• roof caving
• gas explosion mechanism
• frictional effect
• friction speed
• gas combustion ratio