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Rock Mechanics Letters

Open Access Research Article

Theoretical and numerical studies on hydro-mechanical wing crack propagation in precracked rock materials considering T-stress

by Jianli Shao 1  and  Qi Zhang 2,*
1
School of Management Science and Engineering, Shandong Technology and Business University, Yantai, 264005, China
2
Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, 999078, Macau SAR, China
*
Author to whom correspondence should be addressed.
RML  2025 2(4):26; https://doi.org/10.70425/rml.202504.26
Received: 9 October 2025 / Accepted: 24 October 2025 / Published Online: 29 October 2025
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Abstract

To examine the propagation mechanisms of wing cracks in rock under hydro-mechanical interactions, we developed a theoretical model that incorporates compressive loading effects, T-stress, and hydraulic pressure. Complementing this, a coupled hydro-mechanical-damage numerical model was employed for observation and comparative analysis. The influences of water pressure and confining pressure on wing crack evolution were systematically investigated. When T-stress effects are considered, the initiation angle of the compression-shear crack varies with the crack’s inclination, which is consistent with previous experimental results, as opposed to the initiation angle of 70.5° from the traditional theory. In the presence of water pressure, hydraulic forces transmitted within the cracks partially counteract the com-pressive stresses on the crack faces, thereby enhancing tensile damage. This results in an increased mode I stress intensity factor at the wing crack tip in the theoretical model, promoting both crack initiation and propagation. Conversely, an increase in confining pressure elevates compressive stress while reducing shear stress along the crack planes, which delays tensile damage and decreases the mode I stress intensity factor, thus inhibiting wing crack development. The numerical model effectively visualizes both the crack propagation process and the associated flow field, with simulation outcomes demonstrating good agreement with theoretical and experimental results. These findings contribute to a deeper understanding of crack propagation and failure behavior in geotechnical engineering contexts.

Keywords: Wing crack; T-stress; Hydro-mechanical coupling; Stress intensity factor;
Copyright: © 2025 by Shao and Zhang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) (Creative Commons Attribution 4.0 International License). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
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Funding

Start-up Research Grant (SRG) of the University of Macau (SRG2025-00007-FST) , Funding Scheme for Scientific Research and Innovation - Capability Enhancement of The Science and Technology Development Fund, Macao S.A.R. (FDCT) (0046/2025/ITP1)

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ACS Style
Shao, J.; Zhang, Q. Theoretical and numerical studies on hydro-mechanical wing crack propagation in precracked rock materials considering T-stress. Rock Mechanics Letters, 2025, 2, 26. doi:10.70425/rml.202504.26
AMA Style
Shao J, Zhang Q. Theoretical and numerical studies on hydro-mechanical wing crack propagation in precracked rock materials considering T-stress. Rock Mechanics Letters; 2025, 2(4):26. doi:10.70425/rml.202504.26
Chicago/Turabian Style
Shao, Jianli; Zhang, Qi 2025. "Theoretical and numerical studies on hydro-mechanical wing crack propagation in precracked rock materials considering T-stress" Rock Mechanics Letters 2, no.4:26. doi:10.70425/rml.202504.26
APA Style
Shao, J., & Zhang, Q. (2025). Theoretical and numerical studies on hydro-mechanical wing crack propagation in precracked rock materials considering T-stress. Rock Mechanics Letters, 2(4), 26. doi:10.70425/rml.202504.26

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