Abstract Mechanical properties of coal are key factors that influence coal mining and methane extraction. Considering the difficulties in obtaining the mechanical properties of the tectonic coal and some intact coal, uniaxial compression tests were conducted on both types of coal particles in the size range of 0.2–4.0 mm. The force-displacement curves, effective elastic moduli and tensile strengths of the intact and tectonic coal particles were obtained. The power functions were used to describe the distributions of the effective elastic moduli and tensile strengths with the diameters of both coal particles. Statistical distributions of the effective elastic modulus and tensile strength for each coal sample with different particle size intervals were also plotted using a logistic function. The test results revealed that the intact coal shows obvious brittleness, whereas the tectonic coal has a smaller brittleness. The obtained effective elastic modulus and tensile strength of the intact coal are 2.72–4.57 and 2.86–6.35 times those of the tectonic coal, respectively, with particle diameters of 0.2–4.0 mm. The characteristics of low strength and large deformation of the tectonic coal would result in greater difficulty of methane extraction and increased risk during coal mining. Some considerations on the structural model of the tectonic coal and measures to enhance the methane extraction efficiency and reduce the risk of mining were also analyzed.

中文翻译：

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完整煤和构造煤单颗粒压缩力学特性试验研究

摘要 煤的力学性质是影响煤炭开采和瓦斯提取的关键因素。考虑到构造煤和部分完整煤的力学性能难以获得，对粒径范围为0.2-4.0 mm的两种煤颗粒进行了单轴压缩试验。获得了完整和构造煤颗粒的力-位移曲线、有效弹性模量和抗拉强度。幂函数用于描述有效弹性模量和抗拉强度随两种煤颗粒直径的分布。还使用逻辑函数绘制了具有不同粒度间隔的每个煤样的有效弹性模量和拉伸强度的统计分布。试验结果表明，完整煤具有明显的脆性，而构造煤的脆性较小。获得的完整煤的有效弹性模量和抗拉强度分别是构造煤的2.72-4.57和2.86-6.35倍，粒径为0.2-4.0 mm。构造煤强度低、变形大的特点，会导致瓦斯开采难度加大，煤矿开采风险增加。还分析了构造煤的结构模型和提高瓦斯提取效率和降低开采风险的措施的一些考虑因素。分别是构造煤的 35 倍，粒径为 0.2-4.0 毫米。构造煤强度低、变形大的特点，会导致瓦斯开采难度加大，煤矿开采风险增加。还分析了构造煤的结构模型和提高瓦斯提取效率和降低开采风险的措施的一些考虑因素。分别是构造煤的 35 倍，粒径为 0.2-4.0 毫米。构造煤强度低、变形大的特点，会导致瓦斯开采难度加大，煤矿开采风险增加。还分析了构造煤的结构模型和提高瓦斯提取效率和降低开采风险的措施的一些考虑因素。