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以固定轴向应变条件下的轴向应力和径向应变为研究参数,对含瓦斯煤卸围压条件下的力学性质演化规律进行了试验研究,并对各参数的演化规律进行了数学拟合。结果表明,固定轴向应变被逐渐卸除含瓦斯煤的围压后,含瓦斯煤的轴向应力呈分2个阶段逐渐减小的趋势,其减小率与围压、瓦斯压力之差呈正向关系;瓦斯压力越大,卸除单位围压后轴向应力降低越大,轴向应力对卸围压效应越敏感,轴向应力与围压卸除量关系可用二次函数形式表征;固定轴压而逐渐卸除围压时,含瓦斯煤的径向应变呈逐渐增大趋势,瓦斯压力越大卸除单位围压后产生的径向应变越大,径向应变的变化是卸除围压量和瓦斯压力之和的综合作用,径向应变与卸除后的围压关系可用修正对数函数表征。
Taking the axial stress and the radial strain under the condition of fixed axial strain as the research parameters, the evolution of the mechanical properties under unloading confining pressure of coal containing gas is experimentally studied, and the evolution law of each parameter is mathematically fitted . The results show that the axial stress of coal-bearing coal decreases gradually in two stages after the fixed axial strain is gradually released from the confining pressure of gas containing coal gas, and the difference between the reduction rate and the confining pressure and gas pressure is positive The relationship between the axial stress and the discharge of confining pressure can be expressed by the quadratic function. The higher the gas pressure, the larger the axial stress decreases after the confining pressure of the unloading unit is reduced. The axial stress is more sensitive to the unloading confining pressure effect. When the confining pressure is gradually removed by axial compression, the radial strain of gas containing coal gradually increases. The larger the gas pressure is, the larger the radial strain is generated when the confining pressure of the unit is removed, and the change of the radial strain is the displacement Pressure and gas pressure and the combined effect of radial strain and unloading confining pressure can be used to amend the logarithmic function.