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对不同工作面推进速度条件下的超前支承压力演化规律及瓦斯抽采量的变化规律进行了对比分析,对不同轴压卸载起始点、不同围压卸载速度情况下的煤岩固-气耦合规律进行了试验研究.结果表明:轴压、围压同时卸载过程中,煤样经历了应变回弹、应变增加及应变软化3个阶段,轴压卸载起始点越小、围压卸载速度越慢,应变回弹过程越明显.反之,煤样越快进入应变增加和应变软化阶段.固定围压、加载轴压过程中,煤岩渗透率逐渐降低,瓦斯流量变小.轴压、围压同时卸载过程中,煤岩渗透率由缓慢增大到快速增大.当轴压、围压卸载到一定程度后,煤岩渗透率发生突跳.轴压卸载起始点越高、围压卸载速度越快,煤岩渗透率发生突跳时的轴压卸载量越小.
The evolution law of advance support pressure under different working face propulsion speed and the change rule of gas drainage volume are compared and analyzed. The solid-gas coupling of coal and rock under the condition of different initial pressure of unloading and different unloading speed of confining pressure The results show that during the unloading process of axial compression and confining pressure, the coal samples undergo three stages of strain rebound, strain increase and strain softening. The smaller the initial point of unloading, the slower the unloading speed of confining pressure , The more obvious strain rebound process.On the contrary, the faster the coal sample into the stage of strain increase and strain softening.In the process of fixed confining pressure and axial compression, the permeability of coal and rock gradually decreases and the gas flow rate decreases. During the process of unloading, the permeability of coal and rock increases from slowly increasing to rapidly increasing.When the axial pressure and confining pressure are unloaded to a certain extent, the permeability of coal and rock suddenly jumps.The higher the starting point of unloading is, the faster the unloading speed of confining pressure Faster, coal-rock permeability kicking occurs when the axial pressure unloading less.