Influence of freeze-thaw cycles on the shear performance of silty clay-concrete interface

In regions with seasonal frozen soil, mechanical properties of soil are impacted by freeze-thaw cycles, which influence the shear resistance of soil-concrete interface in geotechnical engineering. For evaluating shear properties at the soil-concrete interface, freeze-thaw cycles and direct shear experiments were conducted in this research. The stress-displacement curves, shear strength and parameters of the interface were analyzed in relation to freeze-thaw cycles, while the influences by moisture contents and normal stresses were considered. Results show that the curves related to shear stresses and displacements at the interface are strain-hardening, and shear properties gradually deteriorate with repetitive freezing and thawing. The shear strength is positively related to normal stresses, and it increases by approximately 250% while normal stress varies from 100 to 400 kPa. However, it is negatively correlated with growing moisture contents and freeze-thaw cycles. The reduction in shear strength is about 21%-25% after freeze-thaw cycles, along with a decrease in cohesion ranging from 14% to 20% and for angle of internal friction it reaches at 14%-24%. Moreover, an improved hyperbolic model based on the logistic function and hyperbolic model was established to evaluate shear properties at the interface under freeze-thaw cycles, providing a theory base for engineering construction in seasonally frozen soil regions.