<p>In this paper, a novel multiscale constitutive framework is developed to characterize the mechanical behavior of layered rock (LR) subjected to freeze–thaw (FT) cycles. The formulation is established based on the experimentally observed responses under varying FT cycles, anisotropy angles, and stress states, as presented in the companion paper. The framework consists of two main components, a micro-FT damage model that describes the evolution of FT-induced degradation, and a micromechanical damage model capturing the coupled friction–damage mechanisms of LR under mechanical loading. FT damage is physically related to the progressive structural degradation which is described by a convolutional law. The proposed micro-FT damage model comprehensively accounts for the effects of initial porosity, rock properties, FT environmental conditions, and FT history on the evolution of FT-induced damage. Furthermore, the micromechanical damage model incorporates FT-dependent friction and damage evolution laws to characterize the influence of FT-induced deterioration on the mechanical behavior of LR. For numerical implementation, a fast explicit integration algorithm is employed for FT damage computation, while a multisurface semi-implicit plastic–damage decoupled correction algorithm is adopted to simulate the loading response. The numerical predictions exhibit good agreement with experimental results, demonstrating the accuracy and robustness of the proposed model. Overall, the model effectively captures both the initial and stress-induced anisotropy of LR, as well as their evolution with increasing FT cycles.</p>