A novel low-temperature thermo-mechanical coupling model for frost cracking simulation using the finite-discrete element method

Frost cracking is widely prevalent in cold areas and is typically associated with the deterioration of rock masses. A better understanding of the frost cracking mechanism and precise prediction of the associated crack evolution are essential for the safety and long-term service life of engineered rock structures in cold regions. This paper presents a low temperature thermo-mechanical (TM) coupling modeling framework, implemented into the combined finite-discrete element method (FDEM), to simulate the frost crack evolution in rock masses, considering the heat transfer, water-ice phase transition, and the induced frost heaving pressure. Existing benchmark tests were used to calibrate and verify the proposed modeling framework. Moreover, experimental and numerical results from freezing experiments conducted on samples containing pre-existing cracks have been successfully reproduced the complex mechanisms that lead to crack initiation and propagation in jointed rock formations where cracks driven by the water-ice phase transition initiate and propagate from the pre-existing cracks and deviate under the influence of confining stress and multi-crack interactions (i.e., stress shadow effect). This novel numerical framework presents a potentially useful tool to further understand frost cracking mechanisms and frost crack evolution of engineering projects in cold environments.