Gas-undrained triaxial compression mechanical properties test of layered rock

Authors

Wei WANG, Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China; Institute of Geotechnical Engineering, Hohai University, Nanjing, Jiangsu 210098, ChinaFollow
Xiao LUO, Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China; Institute of Geotechnical Engineering, Hohai University, Nanjing, Jiangsu 210098, China
Chao CHEN, Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China; Institute of Geotechnical Engineering, Hohai University, Nanjing, Jiangsu 210098, China
Shi-fan LIU, Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China; Institute of Geotechnical Engineering, Hohai University, Nanjing, Jiangsu 210098, China
Xue-lei DUAN, Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China; Institute of Geotechnical Engineering, Hohai University, Nanjing, Jiangsu 210098, China
Qi-zhi ZHU, Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, Jiangsu 210098, China; Institute of Geotechnical Engineering, Hohai University, Nanjing, Jiangsu 210098, China

Abstract

In order to study the influence of confining pressure and pore pressure on the mechanical properties and deformation parameters during underground tunnel excavation, a gas-undrained triaxial compression test of layered phyllite was carried out with argon as the permeable medium. The study analyzed the evolution characteristics of stress-strain relationship, peak strength, deformation characteristics and failure modes of layered phyllite with bedding inclinations under varying confining pressure and pore pressure. Additionally, an anisotropy degree formula based on bedding inclinations was introduced to discuss the impacts of confining pressure and pore pressure on the anisotropy of layered phyllite. The results show that the peak strength of layered phyllite increases gradually as the pore pressure decreases or the confining pressure increases. The peak strength c, elastic modulus and deformation modulus exhibit ‘U’ shaped changes with an increase in bedding inclinations. When the bedding inclination ranges between 30° and 60°, the layered phyllite has a low degree of hardness, and the predominant failure mode is shear slip along the bedding plane. Furthermore, the layered phyllite is greatly affected by confining pressure and pore pressure in the direction of parallel bedding, showing significant anisotropic characteristics.

Recommended Citation

WANG, Wei; LUO, Xiao; CHEN, Chao; LIU, Shi-fan; DUAN, Xue-lei; and ZHU, Qi-zhi (2024) "Gas-undrained triaxial compression mechanical properties test of layered rock," Rock and Soil Mechanics: Vol. 45: Iss. 5, Article 4.
DOI: 10.16285/j.rsm.2023.5896
Available at: https://rocksoilmech.researchcommons.org/journal/vol45/iss5/4