Post-peak mechanical property and a new strain softening model for rocks subjected to freeze–thaw cycles

• Published in: Environmental earth sciences 2023-11, Vol.82 (22), p.531, Article 531
• Main Authors: Gao, Feng, Xie, Jinxi, Xiong, Xin, Zhou, Keping
• Format: Article
• Language: English
• Subjects: Biogeosciences; Brittleness; Cohesion; Cold; Cold regions; Compression; Compression tests; Confining; Constitutive models; Deformation; Earth and Environmental Science; Earth science; Earth Sciences; Engineering; Environmental Science and Engineering; Evolution; Freeze thaw cycles; Freeze-thawing; Friction; Geochemistry; Geology; Hydrology/Water Resources; Internal friction; Marble; Mathematical models; Mechanical properties; Modelling; Mohr-Coulomb theory; Original Article; Parameters; Plastic deformation; Rocks; Sandstone; Sedimentary rocks; Stone; Strain; Strain hardening; Strength; Stress-strain curves; Stress-strain relations; Terrestrial Pollution; Triaxial compression tests
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-023-11223-4

In this paper, the mechanical properties and strain softening model of rock in cold regions after the peak were investigated. Freeze–thaw cycle tests and triaxial compression tests were performed on green sandstone to obtain stress–strain curves for rocks under different freeze–thaw cycles. The deformation, strength, and post-peak characteristics of rocks under freeze–thaw cycles and triaxial compression were analyzed, including brittleness and drop degree. On this basis, the experimental data were used to draw the Mohr stress circle and its corresponding envelope under different freeze–thaw cycles and confining pressure conditions. It also determines the generalized cohesion c ¯ and the generalized internal friction angle φ ¯ under different freeze–thaw cycles and confining pressure conditions. Least square surface fitting was used to obtain the softening law of post-peak strength parameters of frozen–thawed rock. Finally, a constitutive model was established that accurately reflects the post-peak strain softening behavior of rock under freeze–thaw cycles. The model uses the maximum principal strain ε 1 as the softening parameter and subjects the strength parameters (generalized cohesion c ¯ , generalized internal friction angle φ ¯ ) to piecewise linear evolution according to the Mohr–Coulomb criterion. The paper concludes by comparing and analyzing the influence of each strength parameter on the post-peak strain softening behavior of rock.