Experimental research on adfreezing strengthsat the interface between frozen fine sand and structures

To explore the mechanisms concerning adfreezing strengths at the interface between frozen fine sand and structures, a series of experiments were conducted using a direct shear apparatus. The main results were as follows: All adfreezing strengths increased with decreasing temperature and increasing normal stress and surface roughness. Peak adfreezing strength (peak shear stress at failure) had a linear relationship with temperature, its relationship with normal stress was in line with the Mohr–Coulomb criterion, and its relationship with roughness satisfied a logarithmic function. Residual adfreezing strength (post-peak shear stress) varied with temperature and normal stress and presented three typical regular patterns—sustained stable, first stable and then fluctuating, and circularly fluctuating. The fluctuation cycle about strength curves increased with increasing roughness. An empirical formula on adfreezing strengths incorporating temperatures, normal stress, and roughness was constructed.