【摘要】 运用自主研发的煤岩细观剪切实验装置,开展了不同成型压力条件下含瓦斯煤剪切破裂过程研究。研究含瓦斯煤剪切破裂过程中微细观裂纹的开裂、扩展、贯通演化规律,对比分析成型压力对含瓦斯煤抗剪强度及剪切破裂最终形态的影响。研究发现:随成型压力增加含瓦斯煤密实度增大,抗剪强度增大;剪切破裂过程裂纹扩展速率与开裂位置偏离预定剪切面距离有关,预定剪切面上剪应力大扩展速率快,偏离预定剪切面扩展裂纹受力减小,扩展速率低,甚至会终止扩展而不能贯通;裂纹扩展形态与成型压力有关,成型压力小,密实度低,抗剪强度低,裂纹容易扩展,剪切带范围小,成型压力大,密实度高,抗剪强度高,裂纹不容易扩展,剪切带范围大;含瓦斯煤剪切破裂过程左侧固定右侧受剪切荷载作用,容易形成雁行排列,为实现最终贯通,破坏雁行排列之间会有张拉牵引裂纹产生。更多还原

【Abstract】 With the self-developed meso-shear test equipment for coal and rock shear fracture tests on coal containing gas were carried out under different molding pressures. The rules of the cracks’ initiation,evolution and transfixion were studied at a mesoscopic level. Also different molding pressure impacts on shear strength and the final shear fracture were analyzed. The results suggest that the coal density and the shear strength increase with the increase of molding pressure. The speed of crack propagation is related to the distance between the predetermined shear plane and the cracking position. On predetermined shear plane the shearing stress is high and the speed is fast,and the propagation crack force decreases as it is away from the predetermined shearing plane,even cannot be transfixed. The crack morphology is related to molding pressure of gas-filled coal. The crack propagation is easy with low molding pressure,low density and shear strength. The crack propagation is difficult with high molding pressure,high density and shear strength. Because the left of the coal is fixed and the right is loaded during the shear fracture process,it is easy to form echelon crack. Eventually the tension cracks will be developed between echelon cracks.更多还原