Experimental study on permeability characteristics for containing-gas raw coal under different stress conditions

The experimental study on permeability characteristics for raw coal under different stress state is implemented by applying the triaxial self-made \"THM coupled with servo-controlled seepage apparatus for containing-gas coal\", the result indicates: The flow rate of coal sample gradually decreases with the nonlinear loading of axial pressure and increases with the nonlinear unloading of axial stress and confining pressure. The flow rate, axial stress and confining pressure curves all satisfy the negative exponential function relation. When the sample reaches the peak intensity, the sample will be destroyed and the stress will drop rapidly, then the flow rate of the sample will increase rapidly. At this stage, the flow rate and axial strain show an oblique \"v\" pattern. The flow rate of coal sample increases nonlinear with the increase of gas pressure, the relation curve between flow rate and gas pressure satisfies power function relation. Under the condition of same confining pressure and ...本研究采用自研含瓦斯煤三轴热-水-力（THM）耦合伺服渗流试验装置，开展了不同应力状态下原煤渗透率特性的试验研究。试验结果表明：煤样渗流速率随轴向压力非线性加载逐渐降低，随轴向应力与围压非线性卸载逐渐升高；渗流速率、轴向应力与围压的变化曲线均满足负指数函数关系。当煤样达到峰值强度时，试样发生破坏且应力快速跌落，此时煤样渗流速率急剧升高，该阶段内渗流速率与轴向应变呈现斜向"V"型变化规律。煤样渗流速率随瓦斯压力升高呈非线性增长，渗流速率与瓦斯压力的关系曲线满足幂函数关系。在相同围压及……条件下