机械振动作用下含瓦斯煤岩渗透率演化规律研究

Study on the Permeability of Gas-bearing Coal under Mechanical Vibration

为研究机械振动对含瓦斯煤岩渗透率演化规律的影响,从应力平衡角度出发,考虑煤岩体受机械振动应力衰减的特殊性,建立振动作用下含瓦斯煤岩渗透率变化方程,求出不同振动时间、孔隙压力和振动频率下含瓦斯煤岩的渗透率。试验发现:机械振动产生的应力波能够加快煤岩体内部裂隙的发育;煤岩渗透率随孔隙压力的变化规律符合Klinkenberg效应。应用渗透率变化方程计算得出的理论值能够较好地反映试验所获得的渗透率演化规律。

In order to study the influence of mechanical vibration on the evolution law of gas-bearing coal and rock,from the point of stress balance,considering the particularity that the stress attenuation of coal and rock mass with mechanical vibration,the permeability change equation of gas-bearing coal under vibration was established,the permeability of gas-bearing rock in different vibration time,pore pressure and vibration frequency was calculated.The result showed that the stress wave generated by mechanical vibration can accelerate the development of cracks in coal and rock mass.The change rule of permeability with pore pressure is in accordance with Klinkenberg effect.The theoretical values obtained by using the permeability change equation can better reflect the evolution law of permeability acquired by the experiment.