不同倾角煤岩组合岩石力学试验及破坏特征

Rock Mechanics Test and Failure Characteristics of Coal-Rock Combination with Different Dip Angles

薄煤层开采条件下多为煤层与岩层复合结构,为提供可靠的开采环境与支护稳定,深入研究煤岩体的岩石力学特征具有重要的意义.通过RMT-150C岩石力学试验机分别对煤岩接触面倾角0°,15°,30°,45°,60°进行一次单轴压缩试验,分析倾角不同的煤岩组合体强度和变形破坏特征.研究结果表明:煤岩组合体的破坏强度接近煤单体的抗压强度,破坏主要集中于煤体部位.对于倾角30°以下裂纹主要分布于煤体,岩体完整性较好.倾角45°以上出现拉剪破坏,裂纹贯穿煤岩体,煤体裂纹多而密集,而岩体出现深部裂纹.在煤体部分与岩体部分峰后破坏后发生明显的滑移现象,主要发生滑移破坏并伴随着拉剪破坏.此外煤体的累计环向应变高于岩体的累计环向应变,煤体的环向应变片破坏30 s左右后岩体开始发生破坏,因此岩体的破坏滞后于煤体.两者破坏整体不一致,具有不均匀性的特征.

Under the mining conditions of thin coal seams,there is mostly a composite structure of coal seams and rock layers.In order to provide a reliable mining environment and support stability,it is of great significance to study the rock mechanics characteristics of coal and rock masses.A series of uniaxial compression experiment were carried out with the RMT-150C rock mechanics testing machine on the dip angle of the coal-rock face at 0°,15°,30°,45°and 60°.Analyze the strength and failure characteristics of coal-rock combination with different dip angles.The research results show that the failure strength of coal-rock combination is close to the compressive strength of coal,and the failure is mainly concentrated in the coal body.For the dip angle below 30°,the cracks are mainly distributed in the coal,and the rock integrity is good.Tensile-shear failure occurs when the dip angle is above 45°,the cracks run through the coal and rock mass.There are many and dense coal mass cracks,while deep cracks appear in the rock mass.Obvious slip phenomenon occurs after the failure of the coal body part and the rock body part after the peak.In addition,the cumulative hoop strain of the coal mass is higher than that of the rock mass,and the rock mass starts to fail about 30 s after the coal mass is damaged.Therefore,the of the rock mass lags behind that of.The damage of the two is inconsistent overall and has the characteristics of unevenness.