Three-dimensional stress-controlled cyclic behavior of the interface between gravel and steel

Abstract

Three-dimensional (3D) stress-controlled cycling is arguably reflective for soil–structure interfaces under in-situ loading conditions. The 3D stress-controlled cyclic behavior of a gravel–steel interface and its influencing factors were explored by conducting several series of tests. Distinct tangential displacement is induced and shows a noticeable coupling effect when subjected to 3D cycling of shear stress. The stress-controlled behavior differs significantly from the displacement-controlled behavior, and presents obvious 3D features which are influenced by the shear path, shear stress amplitude, and unequal stress amplitudes. The shear path affects the magnitude and relationship pattern of the performance parameters, while the shear stress amplitude primarily impacts the magnitude. The shear stress-displacement curves exhibit elliptical and hyperbolic formations in circular and linear shear paths, respectively. The peak reversible normal displacement remains constant with cycling in two-way shear paths, but is negligible in one-way shear path. Increased shear stress amplitude results in magnified tangential displacement and migration, peak shear flexibility, irreversible and peak reversible normal displacements, and decreased non-coaxial angle. The critical shear stress amplitude is approximately 240 kPa, at which the peak shear flexibility remains constant with cycling. Induced aeolotropy of the interface occurs in the reversible normal displacement subjected to unequal stress amplitudes.