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利用自主研发的煤岩细观剪切加载试验装置,开展压剪应力作用下含瓦斯原煤细观裂隙动态演化特征试验研究,描述瓦斯运移通道的形成过程并分析影响细观裂隙形态特征的因素。研究结果表明:裂隙演化为瓦斯入渗煤体并在煤体中运移提供通道;在瓦斯压力及压剪应力的共同作用下,煤体表面破碎、脱落,破碎区更容易演化出新的裂隙。原生裂隙和坚硬颗粒都对细观裂隙演化产生影响:原生裂隙处更容易演化出新裂隙,从而在局部区域形成H型裂隙结构,且新裂隙与原生裂隙交汇时发生移动错位;坚硬颗粒则使得裂隙分叉并绕过自身演化,使得张拉和剪切共同作用形成细观裂隙,裂隙分叉角度为10°~100°,分叉角离散性大;原生裂隙与坚硬颗粒都使得压剪过程中瓦斯在煤体中运移的数目增多。随着法向应力的增大,加上初始损伤和坚硬颗粒的影响,裂隙分布率增大,煤体表面破碎越剧烈。
The experimental study on the dynamic evolution of mesoscale fissures in coal-bearing gas under pressure and shear stress was carried out by using the self-developed meso-meso-scale shear loading test device to describe the formation process of gas migration channel and to analyze the factors affecting the morphological characteristics of meso-fissures . The results show that the fractures evolve into gas infiltration into coal and provide a channel for the migration of coal. Under the joint action of gas pressure and compressive shear stress, the surface of coal is broken, shedding and the fractured areas are more likely to evolve new fractures . Both primary and hard particles have an impact on the evolution of mesoscale fractures: new fractures are easier to evolve at primary fractures, forming H-shaped fractures in local areas and moving dislocations where new fractures intersect with primary fractures; and hard particles Fissure bifurcation and bypass its own evolution, making the tension and shear together to form a meso-fracture, fissure angle of bifurcation 10 ° ~ 100 °, large divergence of the bifurcation angle; both primary cracks and hard particles make the pressure and shear process The number of medium gas transported in the coal body increased. With the increase of normal stress and the influence of initial damage and hard particles, the fracture distribution rate increases and the more severe the coal surface is broken.