Development and Uses of the UCD Hollow Cylinder Apparatus

Abstract

The presentation will describe the development of a versatile hollow cylinder apparatus at UCD in the 1990?s, and its subsequent use in studying the yield behaviour of sand under generalised stress (multi-directional loading) conditions.

The apparatus, which derives its name from the geometry of the test specimen (a hollow cylinder), is the state-of-the-art for testing geomaterials. Hydrostatic confining pressures are applied to its inner and outer wall surfaces, and an axial load and a torque are applied along the length of the specimen. The apparatus is a significant advancement on the traditional apparatus for strength measurement which are, at best, limited to axi-symmetric loading conditions.

In practice, the principal stress axes at a point in the ground rotate during loading. The apparatus can simulate the changing stress regime at a point remote from the centreline of an embankment during construction. Other applications, including a study of the yield behaviour of sedimentary sand deposits, and the validation of existing 2D yield criteria for 3D stress conditions, will be described.