卸轴压起始载荷水平对含瓦斯煤样力学特性的影响

以肥煤制作的型煤试件为研究对象，对其在一定围压和瓦斯压力下的三轴压缩力学特性、不同起始应力点卸轴压时的力学特性进行了试验研究。结果表明：三轴压缩试验型煤试件的变形特点、变形阶段分布与原煤非常相似，而尤以压密阶段和线弹性阶段为最；卸轴压过程中，煤样的变形特性呈非线性特点；随着起始应力点的升高，煤样变形的非线性呈增加趋势，卸轴压过程中的平均弹性模量呈下降趋势，瓦斯压力对煤样变形的影响呈增加趋势；在一定围压和瓦斯压力作用下，煤样卸轴压过程中轴向应力-轴向应变关系可用指数关系表示。

Effect of initial load level of axial unloading on mechanical properties of coal contained gas

Taking briquette samples made of fat coal as the object of study,mechanical properties under triaxial compression and axial unloading of different initial load level in the conditions of certain confining pressure and gas pressure were studied.The results show that the deformation features and deformation phase distribution is very similar with characteristics of raw coal under triaxial compression,especially in compression compacting step and linear elasticity step;nonlinear characteristics are showed in the process axial unloading;nonlinear characteristics are increased as the increasing of initial load level.The average elastic modulus is gradually smaller in process of axial unloading,the effect caused by gas pressure on deformation of coal contained gas is gradually bigger;the relation between axial stress and axial strain of coal contained gas is expressed by exponential equation in process of axial unloading.