Correction method of Mohr-Coulomb strength criterion for rock based on freeze-thaw and residual effects

Abstract

Considering the characteristics of micro element failure when rock is subjected to freeze-thaw and load, based on the impact of reducing the effective bearing area on each damage, the total damage variable and constitutive model of rock under freeze-thaw and load are established. Starting from the characteristics of the entire process of rock deformation, the revised Mohr-Coulomb (M-C) strength criterion of rock is established by considering the freeze-thaw and residual effects. The results show that: The established damage constitutive model fully reflects the entire process of rock deformation and failure, especially the post peak softening and residual deformation characteristics; with the increasing of freeze-thaw cycles, the strength of rock decreases and the deformation increases; with the increasing of confining pressure, the strength and deformation of the rock also increase, which is consistent with the actual situation. This Revised M-C strength criterion introduces the influence of freeze-thaw cycles and residual stress factors, which not only characterizes the relationship between internal stress parameters in rock limit states under different freeze-thaw cycles, but also makes the theoretical data closer to the test data and more in line with practical engineering. Compared with the Drucker-Prager (D-P) criterion, this criterion addresses the disadvantage of the D-P criterion being more conservative. This method is based on the measured results of rock triaxial test, which makes it more flexible and the calculation results closer to reality.