A physically-based elastoplastic damage model for quasi-brittle geomaterials under freeze-thaw cycles and loading

In cold regions, engineering structures are subjected to a combined action of freeze-thaw cycling and loading. The performance degradation of quasi-brittle geomaterials has a sig-nificant influence on the stability of the structures in such areas. In this work, a physically-based elastoplastic damage model for quasi-brittle geomaterials under freeze-thaw cycles and loading is proposed within the framework of irreversible thermodynamics. The inves-tigated material is regarded as a matrix-microcrack composite, in which the microcrack is the physical origin of accumulative damage and nonlinear mechanical behaviors. A new nonlinear evolution law of freeze-thaw damage is introduced based on micro-mechanics. After the decomposition of strain and damage, evolution criteria of closure strain, plastic strain, and loading damage are established, respectively. The incremental constitutive re-lationship then arrives in the framework of thermodynamics. Unlike most existing works, the proposed model is physically-based and shall describe the whole deformation and fail-ure process of quasi-brittle geomaterial under coupled of freeze-thaw cycles and loading. Moreover, for application, a semi-implicit return mapping (SRM) algorithm for the pro-posed model is developed under an arbitrarily loading path. As a heuristic contribution, analytical solutions of the proposed model under conventional triaxial compression are derived, which are used to calibrate the model parameters and to assess the robustness (accuracy and efficiency) of the SRM algorithm. Finally, the proposed model is applied to simulate the whole deformation and failure process of tight sandstone and concrete under freeze-thaw cycles and loading.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

In cold regions, the combined action of freeze-thaw cycling and loading has a significant impact on the stability of engineering structures. This study proposes a physically-based elastoplastic damage model for quasi-brittle geomaterials under freeze-thaw cycles and loading within the framework of irreversible thermodynamics. The model describes the entire deformation and failure process of the material and introduces a new nonlinear evolution law of freeze-thaw damage based on micro-mechanics.