Experimental study on influence of lithology on directional propagation law of type-I cracks

• Published in: Journal of Central South University Vol. 30; no. 10; pp. 3322 - 3334
• Main Authors: Chen, Le-xin, Guo, Wei-yao, Jiang, Yu-jing, Tan, Yan, Zhang, Yue-ying, Lu, Dan, Han, Fei
• Format: Journal Article
• Language: English
• Published: Changsha Central South University 01.10.2023; Springer Nature B.V
• Subjects: Acoustic emission; Crack initiation; Crack propagation; Elastic deformation; Emission analysis; Engineering; Evolution; Lithology; Marble; Metallic Materials; Microcracks; Nucleation; Peak load; Propagation; Sandstone; I型裂纹; 位移场; displacement field; 岩性; 数字图像; lithology; type-I crack; acoustic emission (AE); propagation mechanism; digital image correlation (DIC); 声发射; 扩展机制
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-023-5371-z

To study the influence of lithology on the directional propagation law of rock type-I cracks, a simple crack directional propagation device was used to conduct loading tests on three rock types. The acoustic emission (AE) and displacement field characteristics during crack directional propagation were analyzed, and the propagation mechanism of type-I cracks was discussed. The results indicate that the post-peak load curve of white sandstone showed a gradually decreasing trend, while marble and grey sandstone showed a steep decreasing trend. The AE evolution during crack propagation can be divided into four stages: quiet, slowly increasing, booming, and decreasing. For white sandstone, the duration of the first three stages was short, and the decreasing stage was long. However, the opposite trend was observed for the other types. The crack propagation process includes three stages based on the evolution law of the horizontal displacement field: elastic deformation, microcrack nucleation and coalescence, and crack initiation and propagation. The white sandstone enters the microcrack nucleation and coalescence stage earlier than marble and grey sandstone. The length of the fracture process zone of white sandstone was larger than those of marble and grey sandstone; thus, its crack directional propagation rate and stability were lower.