Experimental study on direct shear behavior of frozen soil-concrete interface

- Temperature-controlled direct shear tests on frozen soil-concrete interface.
- Five stages on the τ¯-u and v-u curves.
- Dependency of peak shear strength and residual shear strength on three factors.
- Mechanisms of shear strength to explain the dependency.

In order to study the mechanical behavior of frozen soil-concrete interfaces, a series of direct shear tests were conducted on a large-scale temperature-controlled direct shear test system (TZJ-150). Synchronous variations were found in both the shear stress-displacement and vertical displacement-shear displacement curves. The whole shear process can be divided into five stages: the elastic deformation part, the plastic deformation part, the whole slide part, the strain hardening part, and the stable residual strength part. The influence rules of normal pressure, temperature, and water content on the shear strength of the interface were obtained by a series of sample tests with different parameters. Fitted equations between factors and shear strength were presented. The peak shear strength had linear relationships with the normal pressure and temperature, but a nonlinear relationship with the water content, which had a much greater effect on the peak shear strength. The residual shear strength also had linear relationships with the normal pressure and temperature, but was basically unrelated with the water content. A reasonable explanation about the changes of peak shear strength and residual shear strength was proposed.