Mechanical properties of a silty clay subjected to freezing–thawing

•Maximum dynamic stress increases after freezing and thawing.•Equivalent diameters and fractal dimension of pores of the thawing soil reduce.•Pore orientation angles are characteristics of centrosymmetric distribution.

The structure of soil will change a lot after freezing and thawing. The mechanical properties and the microstructures are quite different from those of the undisturbed soil. Based on the static triaxial tests and dynamic triaxial tests, this paper studied the mechanical characteristics of a silty clay and quantitatively analyzed the scanning electron microscopy (SEM) images of the silty clay before and after freezing and thawing. According to the static triaxial test and the disturbed state concept (DSC), the constitutive relationship of the thawing soil was investigated. The dynamic triaxial tests were conducted to study the dynamic constitutive relationship of the thawing soil and the mechanical parameters were compared with those of the undisturbed soil. The parameters of the microstructures of silty clay were extracted to analyze the influences of the freezing and thawing on silty soil.