爆破应力波在构造带煤岩的传播规律及破坏特征

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

针对煤矿井下爆破作业扰动到构造带煤岩体容易诱发煤与瓦斯突出事故的现实背景,根据爆破应力波在构造带煤岩的传播规律结合相似模拟实验和数值分析,研究应力波对构造带煤岩的损伤破坏特征及其对煤与瓦斯突出的影响作用机理。研究发现,爆破应力波从岩体传播到构造松软煤层时,在煤岩交界面发生了波的透射和反射;透射的压缩应力波作用于煤体,使煤层裂隙增加;反射的拉伸应力波反作用于岩体,使位于岩体内相应测点的应力值增大约1.1倍,在靠近松软煤体一侧的岩体内形成交叉网状裂纹,加大了岩体的破坏程度和破坏范围。构造松软煤体加强爆破应力波的反射拉伸和爆破振动的累积效应导致构造带煤岩交界面的煤岩体损伤严重,当煤岩体的强度不能抵抗瓦斯内能和煤岩体的弹性潜能时将会发生煤与瓦斯突出。

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.