不同含水状态下含瓦斯原煤加卸载试验研究

以南川宏能煤业(原半溪矿)矿井西翼K1煤层为研究对象,利用自主研制的含瓦斯煤热流固耦合三轴伺服渗流实验装置,进行了不同含水状态下的含瓦斯煤加卸载试验研究。研究结果表明:(1)随含水率增加,加卸载煤样的承载强度、残余强度、变形模量都呈现降低趋势,而轴向应变、径向应变、体积应变及侧向膨胀率均呈增加趋势。(2)加卸载过程中煤样甲烷有效渗透率变化与煤样损伤变形演化相对应,但存在明显的滞后现象;煤样破坏前,含水率越高,甲烷有效渗透率越小;煤样破坏后,含水率越高,甲烷有效渗透率反而越大。(3)随含水率增加,加卸载煤样破坏程度增大,裂隙发育增多,形变量增大,煤样加卸载过程中的总能量和耗散能也增加,而弹性能却减小。

Loading-unloading experiments of coal containing gas under the condition of different moisture contents

The studied specimens are natural coals drilled from the west K1 coal bed of Ban-xi coal mine of Nanchuan-Hongneng Coal Industrial Company，China.By using self-developed “coal containing gas thermal hydrological mechanical (THM) coupling experimental equipment”，an experimental study on the loading-unloading test of coal containing gas was made under the condition of different moisture contents.The research results show that：① With the increase of moisture content，the bearing strength，residual strength and deformation modulus of loading-unloading coal samples all present a trend of decrease.However，the axial strain，lateral strain，volumetric strain and lateral expansion ratio all show a trend of increase；② The change of methane gas effective permeability corresponds with the damage deformation of coal samples，but the curve of methane gas effective permeability lags behind the curve of stress-strain.Before coal samples damage，the higher the moisture content is，the lower methane gas effective permeability is.Conversely，after coal samples damage，the higher the moisture content is，the higher methane gas effective permeability is；③ With the increase of moisture content，the damage，fracture development and deformation of coal samples show a trend of increase.The total energy and the dissipation energy of coal samples present a trend of increase during the whole loading-unloading process，in contrast，the elastic strain energy presents a trend of decrease.