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破碎煤体点载荷强度测试及单轴抗压强度预测分析

Point load strength test of fragile coal samples and predictive analysis of uniaxial compressive strength

  • 摘要: 针对破碎煤体获取标准煤样困难,无法直接获得其单轴抗压强度,采用点载荷仪对现场取得圆柱体和不规则两种形式的破碎煤块进行实验室点载荷强度测试,通过数理统计方法对30组测试数据拟合分析,得出煤块点载荷强度指数分布规律以及与等效直径的关系,同时结合以往单轴抗压强度与点载荷强度指数公式及适用范围,获得新元煤矿破碎煤体单轴抗压强度。研究结果表明:煤块点载荷强度指数遵循Weibull分布,随着块体大小变化其分布形式无显著差别。对点载荷测试数据聚类分析,点载荷强度指数与等效直径成反比。通过分析单轴抗压强度与点载荷强度指数关系,得出新元煤矿巷帮破碎区煤体单轴抗压强度处于0.7~4.9 MPa。研究破碎煤体点载荷强度测试以及定量估计其单轴抗压强度,对破碎煤体巷道围岩支护提供依据具有重要意义。

     

    Abstract: It is difficult to obtain the standard coal samples for the fragile coal samples, and the uniaxial compressive strength cannot be measured directly.The point load meter is used to test the laboratory point load strength of the broken coal in the form of cylinder and irregularity, and the 30 sets of test data are analyzed by mathematical statistics method. The distribution law of coal block point load strength index and its relationship with equivalent diameter were obtained. At the same time, combined with the previous uniaxial compressive strength and point load strength index formulas and its applicable scope, the uniaxial compression strength of fragile coal body in Xinyuan Coal Mine was obtained. The results show that the coal load intensity index follows the Weibull Distribution,and there is no significant difference in the shape distribution with the block size.For the point load test data clustering analysis, the point load intensity index is inversely proportional to the equivalent diameter.By establishing the relationship between uniaxial compressive strength and point load strength index, it is concluded that the uniaxial compressive strength of the coal body in the broken area of Xinyuan Coal Mine is 0.7~4.9 MPa. It is of great significance to study the load strength test of fragile coal body and quantitatively estimate its uniaxial compressive strength, which provides a basis for surrounding rock support of broken coal roadway.

     

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