A constitutive model of freeze–thaw damage to transversely isotropic rock masses and its preliminary application

Abstract

A constitutive model was developed to study damage in transversely isotropic rock masses caused by freeze–thaw cycles. The model was based on the Weibull distribution function, the macroscopic bedding plane damage variable and a new freeze–thaw damage variable. The model was verified by the results of uniaxial and triaxial compression tests of Carboniferous slates at various bedding angles that corresponded to different numbers of freeze–thaw cycles. The predictions of the model and the experimental results followed similar trends. Thus, the model objectively reflected the complete evolution of the stress and strain of a transversely isotropic rock mass due to freeze–thaw cycling. Then, the constitutive model was embedded into UDEC numerical analysis software to analyze the bedding–freeze–thaw stress coupling response of a whole section of the Guanjiao Tunnel during excavation. The results of the calculation accurately reflected the failure mechanism of the rock surrounding the tunnel induced by excavation and correlated with field monitoring data.