In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, th...In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, the volume of coal outbursts and the temperature during the outburst process were studied. The results show that： l） for coal seams with similar structure and com- ponents, two factors, i.e., gas pressure and ground stress affect the volume of coal outbursts, with gas pressure being the more im- portant of the two and 2） the changes in coal temperature, both its increase and decrease, are affected by ground stress and gas pressure, it is a process of change. Preliminary tests show that the system can simulate the dynamic interaction of coal and gas, which is helpful for studying the dynamic mechanism of solid-gas coupling of gas and coal.展开更多
文摘煤的层理面倾角(bedding plane angle,BPA)对射流破岩的效果影响显著。为探讨真三轴应力下不同BPA煤的射流破坏机制,开展了不同BPA煤在真三轴应力下的纯水射流冲蚀试验。结果表明,当煤的BPA较低或较高时,射流冲击分别容易形成锥形破碎坑和裂缝坑,破碎坑开口随着BPA的增大由圆形逐步向椭圆形过渡,煤的破坏模式由剪切破坏主导转变为拉伸-水楔效应主导。随着BPA增至60°,破岩体积增加了154.35%。当施加三轴应力时,煤层理面对射流破煤性能的影响被抑制,不同BPA煤的破坏模式仅呈现圆孔破碎坑,水锤压力引起的剪切破坏是煤在三轴应力下破坏的主要原因,60°BPA煤样的破坏体积减少了95.60%,相比其他倾角降低幅度达到最大。BPA对煤的轴向损伤演化具有驱动作用,随着倾角增大,轴向损伤发生波动。当施加三轴应力时,三轴应力抑制了射流破煤的损伤演化,煤的轴向损伤出现收缩。煤的破碎坑壁面的扫描电子显微镜(scanning electron microscope,SEM)结果表明:当施加三轴应力时,0°BPA煤样的破碎孔壁不再出现微裂隙与脆性剪切破坏的痕迹,并且孔隙的数量与尺寸大幅减小;60°BPA煤样的破碎孔壁不再出现水楔作用导致的大量锯齿状痕迹,三轴应力下不同BPA煤的破碎孔壁面均出现明显的延性剪切破坏特征。
文摘In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, the volume of coal outbursts and the temperature during the outburst process were studied. The results show that： l） for coal seams with similar structure and com- ponents, two factors, i.e., gas pressure and ground stress affect the volume of coal outbursts, with gas pressure being the more im- portant of the two and 2） the changes in coal temperature, both its increase and decrease, are affected by ground stress and gas pressure, it is a process of change. Preliminary tests show that the system can simulate the dynamic interaction of coal and gas, which is helpful for studying the dynamic mechanism of solid-gas coupling of gas and coal.
