Three-Dimensional Direct-Shear Behaviors of a Gravel–Structure Interface

Abstract

Gravel–structure interfaces exist widely in civil engineering practices, and their mechanical behaviors are crucial items in soil–structure interaction analysis. The interfaces are always characterized by three-dimensional (3D) features, which seldom have been explored. This paper presents the 3D behaviors of a gravel–structure interface from large-scale two-way beeline, cross, circular, and arc shear tests. The normal displacement can be divided into irreversible and reversible components. The shear stress–displacement hysteretic relationship exhibits an elliptical response in circular shear paths, other than the hyperbolic trend observed in linear shear paths. The shear strength is isotropic, and behaves in accordance with the Mohr–Coulomb failure criterion. The shear path plays a significant role in the 3D interface behaviors. Good consistency is found to exist in the irreversible normal displacement versus shear work density relationship, the reversible normal displacement versus resultant tangential displacement relationship, and the resultant shear stress versus resultant tangential displacement hysteretic relationship, regardless of the shear paths.