Experimental and analytical investigation of Frost heave characteristics in red-bed coarse-grained materials incorporating particle breakage effect

The eastern part of the Qinghai-Tibet Plateau is located in the high-altitude freeze-thaw region, where terrestrial clastic red beds formed by sedimentation since the Mesozoic are widely distributed. Recently, red-bed coarse-grained materials (CGMs) have been increasingly utilised in construction in projects across western China. However, owing to the high degree of weathering and low strength, red-bed CGMs are susceptible to particle breakage under impact loads during compaction. This process results in an increased fine particle content (FC), which exacerbates frost heave during the service period, significantly compromising engineering stability. This study investigates the particle breakage and frost heave characteristics of red-bed CGMs, focusing on the effects of water content (w), initial fine particle content (FC₀), and the number of freeze-thaw cycles (N_FT). Based on experimental data, a frost heave ratio prediction model incorporating particle breakage effects was developed. This model accounts for the influence of w, FC₀, and N_FT on the frost heave ratio of red-bed CGMs, offering a scientific foundation for evaluating the suitability of these materials as engineering fillers in high-altitude freeze-thaw regions.