Micromechanically inspired investigation of cemented granular materials: part II - from experiments to modelling and back

Abstract

This paper presents an experimental and analytical/numerical study of the mechanics of cemented granular materials (CGMs). This study incorporates both in situ X-ray tomography and regularised finite element simulations, whose combination offers a unique, complementary insight into the multiscale processes that drive the mechanical response of CGMs. Being the second in a set of a two-part contribution, this paper takes advantage of the image analysis tools developed in Part I to quantitatively explore the effects of boundary conditions on grain-scale processes as well as material properties. We reveal, for example, the influence of the degree of cementation on the spatial distribution of damage and suggest the existence of a local ultimate cement size distribution that is independent from the initial cement content. This paper also validates the predictions of a micromechanically inspired constitutive model at three different scales: in terms of the macroscopic response, the mesoscopic emergence of localisation patterns and the evolution of microscale inelastic processes. A unique feature that sets our model apart from previous CGM models is the adoption of only measurable internal variables, capable of representing grain-scale processes such as the damage of cement bridges. Its statistically representative experimental quantification is found to be in good agreement with the model predictions.