Frost Crack Propagation and Interaction in Fissured Rocks Subjected to Freeze–thaw Cycles: Experimental and Numerical Studies.

Frost crack evolution induced by cyclic freeze–thaw is responsible for rock deterioration in cold regions and poses major threats to public safety, engineering structures, and alpine slope stability. This paper presents experimental and numerical works aimed at investigating the frost crack evolution in fissured rock masses, as well as the interaction between frost cracks. A series of laboratory freezing experiments are conducted on rock-like specimens with various pre-existing fissures. Experimental results show that frost cracks initiate at the pre-existing fissure tips and propagate under the freeze–thaw treatment. Moreover, the frost crack evolution is significantly influenced by external stress conditions and frost crack interactions, forming several typical propagation patterns (e.g., deflection, coplanar and butterfly shape, etc.). Then, numerical simulations with a low-temperature thermal–mechanical coupled model, where the water/ice phase transition and hence volume expansion are explicitly simulated, are conducted to reproduce the experimental observation. The numerical results are consistent with the experimental observations and help to reveal the underlying mechanisms of the frost crack growth and frost crack interaction. This experimental and numerical investigation helps to improve the understanding of frost cracking mechanisms that can inform engineering design in cold regions with fissured rock masses. Highlights: Frost crack propagation and interaction under freeze-thaw cycles are investigated. Frost heaving pressure induced by ice expansion is large enough to drive crack propagation. Confining stresses alter the stress field around the crack tips, inducing crack orientation. Mutual interaction between adjacent frost cracks significantly affects the cracking pattern. Novel low-temperature thermal-mechanical coupling model is developed for frost cracking problems. [ABSTRACT FROM AUTHOR]