Rock strength weakening subject to principal stress rotation: Experimental and numerical investigations

• Published in: Journal of Rock Mechanics and Geotechnical Engineering Vol. 16; no. 9; pp. 3544 - 3557
• Main Authors: Liu, Huandui, Wang, Guibin, Yang, Chunhe, Zhang, Junyue, Chen, Shiwan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2024; University of Chinese Academy of Sciences,Beijing,100049,China%State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China%State Key Laboratory of Coal Mine Disaster Dynamics and Control,College of Resources and Environmental Sciences,Chongqing University,Chongqing,400044,China%College of Resources and Environmental Engineering,Guizhou University,Guiyang,50025,China; State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China; Elsevier
• Subjects: Fracture mechanics; Hollow cylinder torsional apparatus for rock (HCAR); Particle flow method; Principal stress rotation (PSR); Rock strength; Rock strength; Hollow cylinder torsional apparatus for rock (HCAR); Fracture mechanics; Principal stress rotation (PSR); Particle flow method; Principal stress rotation(PSR); Hollow cylinder torsional apparatus for rock(HCAR)
• ISSN: 1674-7755
• DOI: 10.1016/j.jrmge.2024.04.004

During the construction and operation of gas storage reservoirs, changes in the principal stress direction can induce fracture propagation under conditions of lower differential stress, potentially leading to failure in the surrounding rock. However, the weakening of strength due to pure stress rotation has not yet been investigated. Based on fracture mechanics, an enhanced Mohr-Coulomb strength criterion considering stress rotation is proposed and verified with experimental and numerical simulations. The micro-damage state and the evolution of the rock under the pure stress-rotation condition are analyzed. The findings indicate that differential stress exceeding the crack initiation stress is a prerequisite for stress rotation to promote the development of rock damage. As the differential stress increases, stress rotation is more likely to induce rock damage, leading to a transition from brittle to plastic failure, characterized by wider fractures and a more complex fracture network. Overall, a negative exponential relationship exists between the stress rotation angle required for rock failure and the differential stress. The feasibility of applying the enhanced criterion to practical engineering is discussed using monitoring data obtained from a mine-by tunnel. This study introduces new concepts for understanding the damage evolution of the surrounding rock under complex stress paths and offers a new theoretical basis for predicting the damage of gas storage reservoirs.