Microcrack evolution law and interaction mechanism of coal with multiple cracks

被引：0

作者：

Wang L. ^{[1
]}

Shang R. ^{[1
]}

Liu H. ^{[1
,2
]}

Zhu C. ^{[1
]}

Chen L. ^{[1
]}

Fan H. ^{[1
]}

Li S. ^{[1
]}

Zou P. ^{[1
]}

机构：

[1] State Key Laboratory of Mine Response and Disaster Prevention and Control in Deep Coal Mine, Anhui University of Science and Technology, Anhui, Huainan

[2] School of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing

来源：

Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | 2023年 / 52卷 / 02期

关键词：

coal containing multi-fractures; crack propagation; digital image related methods; interaction mechanism; particle flow simulation; stress intensity factor;

D O I：

10.13247/j.cnki.jcumt.20220639

中图分类号：

学科分类号：

摘要：

The fractures in the coal body are characterized by random distribution, and their position distribution and interaction under load could affect the stability of the coal body. In this study, uniaxial compression experiments with random three-fracture coal samples were performed to elucidate the evolution law and interaction mechanism of multi-fracture propagation in coal. Beyond that, the digital image correlation method (DIC) was used to monitor the deformation process of the test sample, and the evolution process of crack gestation, propagation and penetration was verified by numerical simulation from meso-angle. Based on the classical Kachanov method and stress field analysis, the stress intensity factor expression of the three fracture tips of finite plates under uniaxial compression state was derived and verified. According to the results, the crack-to-crack interaction influences the tip stress intensity factor in three forms: "increase, decrease and no effect". According to the derived stress intensity factor expression of the multi-fracture tip of the finite plate, the fracture tip stress level is calculated. Moreover, the fracture tip fracture position can be accurately predicted in combination with the strain energy density factor criterion;The fracture position distribution has an obvious guiding effect on the formation of a local high strain zone in the initial strain field, which is specifically manifested as follows: the specimen is first damaged at the tip of each fracture in the early stage of loading and gradually evolves into a local high strain zone. After expansion, a high strain concentration zone is formed and then serves as the corresponding expansion path of macroscopic cracks. The form of specimen failure is shear and tension failure. Apart from that, the new crack appears in the form of shear in the early stage of loading, and an airfoil crack is formed at the tip of the fracture. In addition, the number of tensile cracks grows rapidly with the continuous application of load, which eventually induces the instability of the sample. © 2023 China University of Mining and Technology. All rights reserved.

引用

页码：300 / 313

页数：13

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