Wang Ziping, Li Shengwei, Zhang Yi, Qi Peiwen, Zhang Youyou, Chen Yuanjing, Li Yexue, Zeng Gang
School of Civil Engineering and Architecture, Hubei University of Arts and Science, Xiangyang, 441053, Hubei, China.
State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resources and Hydropower, Sichuan University, Chengdu, 610065, China.
Sci Rep. 2024 Jun 10;14(1):13283. doi: 10.1038/s41598-024-64342-8.
The tensile properties of coal under dynamic loading are important mechanical characteristics of coal and are highly important for controlling coal rock stability under impact loading conditions, selecting blasting engineering parameters, and studying the mechanism of rockburst disasters. To investigate the dynamic tensile failure process of coal subjected to impact loading, this study used high-speed photography and digital image correlation technology to capture the dynamic tensile failure of coal under impact loading. The dynamic tensile evolution was quantitatively analyzed from the beginning of coal sample being loaded to failure. The captured images of the coal were processed, and the fractal dimension was used to quantitatively describe the evolution of the coal surface cracks under impact loading. The following conclusions were drawn from the experimental results: (1) An empirical formula was established to describe the dynamic tensile strength characteristics of coal under different loading rates. (2) Under impact loading, the maximum strain of a Brazilian disc coal sample first appeared at the contact end between the sample and the incident rod. (3) Under impact loading, a Brazilian disc coal sample cracked from the center of the sample outward, and the crack subsequently extended toward both ends. The fractal dimension of the crack exhibited a power function relationship with time, and the variation range of the fractal dimension of the crack was 1.05-1.39.
煤在动态加载下的拉伸特性是煤的重要力学特性，对于控制冲击加载条件下的煤岩稳定性、选择爆破工程参数以及研究岩爆灾害机理具有极其重要的意义。为了研究煤在冲击加载下的动态拉伸破坏过程，本研究采用高速摄影和数字图像相关技术来捕捉煤在冲击加载下的动态拉伸破坏。从煤样加载开始到破坏，对动态拉伸演化进行了定量分析。对采集到的煤的图像进行处理，并用分形维数定量描述冲击加载下煤表面裂纹的演化。从实验结果得出以下结论：（1）建立了一个经验公式来描述不同加载速率下煤的动态拉伸强度特性。（2）在冲击加载下，巴西圆盘煤样的最大应变首先出现在试样与入射杆的接触端。（3）在冲击加载下，巴西圆盘煤样从试样中心向外开裂，裂纹随后向两端扩展。裂纹的分形维数与时间呈幂函数关系，裂纹分形维数的变化范围为1.05 - 1.39。
