含瓦斯煤岩卸围压力学特性及能量耗散分析

摘要

A series of confinement unloading tests were performed on coal specimens containing gas using a servo-con- trolled Triaxial Stress Thermal-hydrological-mechanical Coal Gas Permeameter to investigate the gassy specimens' me- chanical responses and energy dissipation characteristics. Experimental results show that the speed of unloading the confining the speed be related correlated pressure is positively related to the instability process of gassy coal. A coefficient,reflecting the influence of of unloading confinement on the mechanical behavior of coal, is defined accordingly which has been found to exponentially to the confinement unloading speed. The speed of unloading confining pressure is negatively to strains with methane gas pressure and differential pressures being constant, suggesting that an increase in the unloading speed means a decreasing strains at failure. In addition, the confinement unloading decreases with a mounting confinement unloading amount of energy dissipated in the process of speed.%利用自主研制的含瓦斯煤岩热流固耦合三轴伺服渗流装置对含瓦斯煤岩进行了三轴卸围压试验,基于实验结果,研究了含瓦斯煤岩卸围压失稳破坏过程中的力学特性及其能量耗散规律。结果表明：在初始瓦斯压力和围压相同的情况下,卸围压速率增大加快了含瓦斯煤岩失稳破坏的进程,定义的卸围压效应系数反映了三轴卸围压实验中卸围压速率对含瓦斯煤岩失稳破坏难易程度,且卸围压效应系数与卸围压速率之间存在幂函数的关系;在瓦斯压力和应力差相同的情况下,不同卸围压速率下含瓦斯煤岩的轴向应变、侧向应变和体积应变的变化规律具有较好的一致性,卸围压速率越大,含瓦斯煤岩的轴向应变、侧向应变和体积应变越小;卸围压过程中能量耗散与卸围压速率有关,且含瓦斯煤岩的能量耗散随着卸围压速率的增大而减小。