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通过对宾夕法尼亚州4个煤层煤的抗压强度测定,得出同一个煤层和不同煤层之间煤的抗压强度值是不同的。从12个煤矿(每个煤层3个煤矿)取大块煤样,然后用低速锯条将其切割成边长为500mm的立方体试样,进行抗压强度试验,其结果用于计算实际煤柱强度。采用受护面积法确定煤柱应力,由煤柱应力和煤柱抗压强度计算每个煤柱的安全系数。还把立方体煤样的抗压强度与煤的物理化学性质(容重、水分、灰分、含硫量和含碳量)进行相关分析,确定它们之间是否存在较强相关关系。煤的平均抗压强度变化从下凯它宁煤层的9.1MPa至匹兹堡煤层的37.8MPa,不同煤层之间煤柱强度变化范围为29.5～48.1MPa。试验发现煤的抗压强度除了与含碳量有关外,与其他物理化学性质无关。由于防止煤柱破坏的安全系数值通常都超过所建议采用值2,现有的煤柱几乎都设计过大,这说明准确地估算煤的抗压强度,可使煤柱设计得较为合理(减小煤柱尺寸),从而增加煤炭生产量。
Comparing the compressive strength of four coal seams in Pennsylvania, it is found that the compressive strength of coal in the same seam and different coal seams is different. A large sample of coal was taken from 12 coal mines (3 coal mines per coal seam) and then cut into cube specimens with a side length of 500 mm using a low-speed saw blade for compressive strength tests, the results of which were used to calculate the actual coal pillar strength . The area of coal pillar is determined by the area under protection, and the safety factor of each coal pillar is calculated from the stress of coal pillar and the compressive strength of coal pillar. Cube coal samples also compressive strength and physical and chemical properties of coal (bulk density, moisture, ash, sulfur content and carbon content) correlation analysis to determine whether there is a strong correlation between them. The average compressive strength of coal varied from 9.1 MPa in Xiakaiitining coal seam to 37.8 MPa in Pittsburgh coal seam, and the coal pillar strength varied from 29.5 to 48.1 MPa between coal seams. The test found that the compressive strength of coal in addition to the carbon content, with nothing to do with other physical and chemical properties. Since the safety factor to prevent coal pillar damage usually exceeds the recommended value of 2, almost all of the existing coal pillar designs are too large. This shows that accurate estimation of coal compressive strength can make the coal pillar more reasonable Small coal pillar size), thereby increasing coal production.