Experimental Study On The Impact Of Three Zones Gas Migration And Explosion Influenced By Roof Collapse In The Goaf Nearby Return Airway

Gas explosion is one kind of common mine disasters and its destruction is huge, then it brings the very big trouble to the normal production of coal mine. Many mining experts and scholars on gas explosion have studied so long time, but the reaction of gas explosion is very complex, so there has not been very good measures to prevent gas explosion. This paper summarizes the results of previous studies; simply introduces roof falls down mechanism, gas explosion mechanism, the three belts and fire mined-out area. Emphatically from the impact of roof periodic fall to the gas migration, using the laboratory and computer analog simulation numerical simulation method, in view of the different roof collapse and step, make hundreds of repeated the experiment in site of three zones and summarize the main following conclusion:1. With the same cycle fall step roof of goaf,gas flow differently in the three zones.The main differences are mainly embodied in the direction of gas flow rate, as well as whether causing gas-forth movement direction of change.2. Different kinds cycle of fall step of roof, to the same points in the gas-forth movement direction is different, the mainly embodies is same to the one points. If different cycle of fall step roof with different points in the gas,three are the bigger impact and more differences.3.Before the roof fall down felling in the seepage free projection of the pressure taking step distance is special and its cross behind the gas migration caused by one-way movement.4. The gas in the weak seepage in the migration back and forth with the more times, and three may be fire point of the greater the probability to meet, produce gas explosion of the greater the probability.