粉煤瓦斯解吸实验是研究粉煤瓦斯解吸动力学特征的常用手段之一,其结果是揭示粉煤放散瓦斯能力的重要参数。传统实验方法在煤样罐泄压后开始测量瓦斯解吸数据,存在较大误差。利用甲烷与氦气的粉煤吸附特性差异性提出了改进的粉煤瓦斯解...粉煤瓦斯解吸实验是研究粉煤瓦斯解吸动力学特征的常用手段之一,其结果是揭示粉煤放散瓦斯能力的重要参数。传统实验方法在煤样罐泄压后开始测量瓦斯解吸数据,存在较大误差。利用甲烷与氦气的粉煤吸附特性差异性提出了改进的粉煤瓦斯解吸实验方法,并建立了初始瓦斯粉煤快速解吸模型,从而揭示了煤体粉化后瓦斯快速解吸的内在机制。研究结果表明:解吸开始的前5 s,0.075~0.150 mm JG71煤样解吸的瓦斯量是1.00~2.36 mm煤样的2.05倍,而0.075~0.150 mm JG82煤样解析的瓦斯量是1.00~2.30煤样的10.29倍;煤样粉化程度越高,吸附平衡压力越大,初始瓦斯解吸速度越大,传统实验方法得到的数据误差越大。研究结果为突出粉化煤体快速解吸瓦斯、提供瓦斯膨胀能、促进煤与瓦斯突出传播的研究提供了数据支撑,同时为完善煤与瓦斯致灾机理奠定基础。展开更多
Accurate assessment of coal brittleness is crucial in the design of coal seam drilling and underground coal mining operations.This study proposes a method for evaluating the brittleness of gas-bearing coal based on a ...Accurate assessment of coal brittleness is crucial in the design of coal seam drilling and underground coal mining operations.This study proposes a method for evaluating the brittleness of gas-bearing coal based on a statistical damage constitutive model and energy evolution mechanisms.Initially,integrating the principle of effective stress and the Hoek-Brown criterion,a statistical damage constitutive model for gas-bearing coal is established and validated through triaxial compression tests under different gas pressures to verify its accuracy and applicability.Subsequently,employing energy evolution mechanism,two energy characteristic parameters(elastic energy proportion and dissipated energy proportion)are analyzed.Based on the damage stress thresholds,the damage evolution characteristics of gas bearing coal were explored.Finally,by integrating energy characteristic parameters with damage parameters,a novel brittleness index is proposed.The results demonstrate that the theoretical curves derived from the statistical damage constitutive model closely align with the test curves,accurately reflecting the stress−strain characteristics of gas-bearing coal and revealing the stress drop and softening characteristics of coal in the post-peak stage.The shape parameter and scale parameter represent the brittleness and macroscopic strength of the coal,respectively.As gas pressure increases from 1 to 5 MPa,the shape parameter and the scale parameter decrease by 22.18%and 60.45%,respectively,indicating a reduction in both brittleness and strength of the coal.Parameters such as maximum damage rate and peak elastic energy storage limit positively correlate with coal brittleness.The brittleness index effectively captures the brittleness characteristics and reveals a decrease in brittleness and an increase in sensitivity to plastic deformation under higher gas pressure conditions.展开更多
文摘粉煤瓦斯解吸实验是研究粉煤瓦斯解吸动力学特征的常用手段之一,其结果是揭示粉煤放散瓦斯能力的重要参数。传统实验方法在煤样罐泄压后开始测量瓦斯解吸数据,存在较大误差。利用甲烷与氦气的粉煤吸附特性差异性提出了改进的粉煤瓦斯解吸实验方法,并建立了初始瓦斯粉煤快速解吸模型,从而揭示了煤体粉化后瓦斯快速解吸的内在机制。研究结果表明:解吸开始的前5 s,0.075~0.150 mm JG71煤样解吸的瓦斯量是1.00~2.36 mm煤样的2.05倍,而0.075~0.150 mm JG82煤样解析的瓦斯量是1.00~2.30煤样的10.29倍;煤样粉化程度越高,吸附平衡压力越大,初始瓦斯解吸速度越大,传统实验方法得到的数据误差越大。研究结果为突出粉化煤体快速解吸瓦斯、提供瓦斯膨胀能、促进煤与瓦斯突出传播的研究提供了数据支撑,同时为完善煤与瓦斯致灾机理奠定基础。
基金Project(52274096)supported by the National Natural Science Foundation of ChinaProject(WS2023A03)supported by the State Key Laboratory Cultivation Base for Gas Geology and Gas Control,China。
文摘Accurate assessment of coal brittleness is crucial in the design of coal seam drilling and underground coal mining operations.This study proposes a method for evaluating the brittleness of gas-bearing coal based on a statistical damage constitutive model and energy evolution mechanisms.Initially,integrating the principle of effective stress and the Hoek-Brown criterion,a statistical damage constitutive model for gas-bearing coal is established and validated through triaxial compression tests under different gas pressures to verify its accuracy and applicability.Subsequently,employing energy evolution mechanism,two energy characteristic parameters(elastic energy proportion and dissipated energy proportion)are analyzed.Based on the damage stress thresholds,the damage evolution characteristics of gas bearing coal were explored.Finally,by integrating energy characteristic parameters with damage parameters,a novel brittleness index is proposed.The results demonstrate that the theoretical curves derived from the statistical damage constitutive model closely align with the test curves,accurately reflecting the stress−strain characteristics of gas-bearing coal and revealing the stress drop and softening characteristics of coal in the post-peak stage.The shape parameter and scale parameter represent the brittleness and macroscopic strength of the coal,respectively.As gas pressure increases from 1 to 5 MPa,the shape parameter and the scale parameter decrease by 22.18%and 60.45%,respectively,indicating a reduction in both brittleness and strength of the coal.Parameters such as maximum damage rate and peak elastic energy storage limit positively correlate with coal brittleness.The brittleness index effectively captures the brittleness characteristics and reveals a decrease in brittleness and an increase in sensitivity to plastic deformation under higher gas pressure conditions.
