Laboratory Creep Parameter Determination of Sand–TDA Mixtures with Subsequent FEM Validation

Abstract

This study is part of an experimental program that was conducted to determine the elastic, plastic and creep parameters of TDA–sand granulated mixtures. However, this paper emphasizes only the obtention of creep parameters for use in constitutive equations. This was attained by considering sand specimens, at a predetermined TDA volumetric content, which were restrained laterally and loaded axially with a total stress increment of long duration. The measured results clearly indicated a primary creep phase that rapidly transitioned into a secondary stationary creep phase, never attaining the tertiary phase. The magnitude of the creep strain was strongly affected by the TDA volume fraction content. Moreover, at a constant TDA volume fraction content, the creep strain rate increased with applied load. This trend was observed in all of the tests, with the difference that the magnitude of the strain rate depends on the applied stress and TDA volume fraction content. This observation conduced the adoption of the Bailey–Norton law as a possible constitutive model for creep of TDA–sand mixtures. The multi-axial extension of this creep law was then used in a commercial FEM code to simulate the creep behavior of a rigid circular plate resting on a TDA–sand mixture. This simulation was then verified via a small-scale laboratory test of the same problem.