AUTHOR=Li Hua , Wang ZhiPeng , Dai Lingquan , Wan Liangpeng , Deng Huafeng , Yang Chao , Chen Jianghong , Pan Hongyue , Wang Lei , Jiang Qiao 

TITLE=Critical Damage and Microstructure Characteristics of Sandstone in the Three Gorges Reservoir Area by Single Specimen Method Under Different Stress Paths

JOURNAL=Frontiers in Physics

VOLUME=Volume 9 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2021.775459

DOI=10.3389/fphy.2021.775459

ISSN=2296-424X

ABSTRACT=Residual strength Parameters and critical damage value of rock is the important parameters of stability analysis of engineering rock mass. Based on the previous single test method, this paper combined with the deformation characteristics of rock residual phase under different stress paths, proposing a single specimen repeated loading method to measure the residual strength Parameters of the rock under different stress paths, obtaining the critical damage value of rock based on different damage variables. And proposed to modify the critical damage value based on residual constitutive energy. Improve the definition of damage variables based on constitutive energy dissipation. According to the microstructure characteristics of the rock sample, the mechanism of the single specimen method to determine the critical value of rock sample damage is revealed. The results show that: (1) Comparing the results of triaxial failure test of rock under different stress paths and single specimen repeated loading test, the residual strength of rock sample is mainly controlled by confining pressure of loading, which is not obvious relationship with initial confining pressure and stress path. (2) The number of repeated compression has little effect on the internal structure, particle flatness and particle surface smoothness of their specimens, which is reflected to the macroscopic level that the residual strength of sandstone tends to a stable value; (3) The corrected critical damage value based on residual strain energy is closer to the theoretical value. Test methods in this paper can provide useful reference for determination of residual strength parameters and critical damage value.