Propagation law and failure characteristics of blasting stress wave in structural belt coal-rock

In terms of coal and gas outburst accidents frequently caused by blasting in geological structural belt, according to the propagation law of blasting stress wave in structural belt coal-rock, combined with simulation test and numerical simulation, the damage and failure rules of coal and rock in structural belt disturbed by blasting stress waves and their effects on coal and gas outbursts were studied.It is found that when the blasting hole enters into the soft coal seam from the rock layer, the stress wave will reflect and transmit at the interface of coal and rock. The transmitted compressive stress wave acts on the coal body which increases the seam crack, the reflected tensile stress wave reacts to the rock which causes the stress values of the corresponding measuring points in the rock increase by about 1. 1 times, the cross network cracks occur within the rock near the soft coal body, and increases the rock failure and damage extent.The soft coal bodies in tectonic zone will strengthen the reflection of blasting stress wave and with the cumulative effect of blasting vibration, which lead to the interface of coal and rock in the tectonic zone are seriously damaged.When the strength of coal and rock mass can not resist the internal energy of gas and the elastic potential of coal and rock mass, the outburst of coal and gas will occur.