循环载荷下突出煤样的变形和渗透特性试验研究

 以典型煤与瓦斯突出矿井——天府煤业有限责任公司三汇一矿K1煤层原煤制备的煤样为研究对象，利用自行研制的含瓦斯煤热流固耦合三轴伺服渗流系统，进行固定瓦斯压力及不同围压情况下突出煤试样循环载荷下渗流试验研究。研究结果表明：在循环载荷作用下，煤样产生塑性变形，煤样的弹性模量和渗透率随着循环次数增加呈下降趋势，且在第一循环下降最为明显；卸载过程中渗透率逐渐增大，加载过程中渗透率逐渐减小，卸载和加载时的渗透率–应变曲线围成一个封闭环，与轴向应力–应变曲线形成的封闭滞回环相对应，说明渗透率的变化与煤样的损伤变形密切相关；渗透率变化率和损伤变量呈正相关变化，前几个循环变化较为明显，经过之后几个循环，其数值趋于稳定。

EXPERIMENTAL STUDY ON DEFORMATION AND SEEPAGE PROPERTIES OF OUTBURST COAL SAMPLES UNDER CYCLIC LOADING

Based on the typical coal and gas outburst K1 coal seam of Sanhui mine which belongs to Tianfu Coal Industry Co., Ltd.，the seepage experiments of outburst coal samples under cyclic loading，constant gas pressures and different confining pressures are conducted by self-developed fluid-solid-heat coupling triaxial servo-controlled seepage system of coal containing gas. The research results show that plastic deformation of coal sample is produced under cyclic loading. With the cyclic number，its elastic modulus and permeability both tend to decrease which is the most obvious in the first cycle. The permeability of coal samples gradually increases in unloading process and decreases in loading process. Closed rings are formed in the permeability-strain curves in the two above processes，corresponding to a closed hysteresis loop formed in axial stress-strain curve，which indicates that permeability changes is closely related to the damage deformation of coal sample. What¢s more，permeability rate is positively correlated with damage variable. The variation is more obvious in the previous cycles and tends to be stable after the later cycles.