充填物性质影响结构面剪切特性试验研究

通过自主研发的煤岩剪切-渗流耦合试验装置，开展了无充填结构面和充填石膏、岩屑、黄泥结构面的剪切试验。利用三维光学扫描技术，研究了结构面的三维形貌特征和裂隙开度演化。结果表明：充填结构面的峰值剪应力和法向位移由充填石膏、岩屑到黄泥依次递减，受充填物强度影响较大；无充填结构面由于直接接触，剪切后表面发生明显磨损，结构面粗糙度系数（JRC）整体减小且变化最为显著，充填石膏和岩屑结构面的JRC变化次之，充填黄泥结构面几乎没有变化；充填物破坏和结构面磨损主要受裂隙开度演化和局部应力集中的影响。随着剪切位移的增大，在裂隙开度较小的区域，应力分布较大，充填物易沿此处破碎，无充填结构面沿此处严重磨损。

Experimental study on shear behavior of joints filled with different materials

Based on the self-developed shear-seepage coupling test device for coal rock, a series of direct shear tests was performed on the unfilled joints and joints filled with gypsum, debris, and clay. The 3D optical scanning technology was also employed to examine the morphology and aperture evolution of joints during shearing. The results show that peak shear stress and normal displacement of joints exhibit same regularity, which decreases as filling material varies from gypsum, debris to clay, showing that the nature of filling materials contributes significantly to the shear properties of joints. Unfilled joint is evidently worn after shearing and its JRC decreases most significantly due to direct contacting between the upper and lower surfaces. The JRC of joints filled with gypsum and debris changes relatively little, while it remains nearly the same for joints filled with clay. The materials failure and surface abrasion are mainly controlled by the aperture evolution and local stress concentration. With shear displacement increasing, stress concentrates in the region aperture decreases, where materials failure and abrasion of unfilled joints occurred.