Investigation of the load sustaining micro mechanisms of cemented sand using the mesoscale FEM approach

Abstract

While the mechanics of cemented granular material have already been approached by means of constitutive modeling, the capacity of introducing the precise internal structure of multiphase media in numerical simulations offers an alternative perspective of investigation. In specific, means of X-ray computed tomography are able to quantify the internal irregular geometry of the composite material in the form of three-dimensional images. Image analysis can be applied in order to distinguish the topology of each material phase and advanced meshing techniques are able to form a twin meshed domain. The current paper deals with the quantitative description of the morphology of small cemented sand samples, the application of developed image analysis algorithms to treat imaging artefacts (mainly due to beam hardening), the equivalent mesh generation via the image adapted meshing technique and the numerical testing using the Finite Element Method. Four samples are imaged, meshed and numerically tested in uniaxial compression; the mesoscale finite element simulations are able to display the intergranular stress transmission chains. A statistical analysis of the load carried by the granular skeleton provides evidence of the influence of the cementation degree and the compaction of the aggregates on the uniformity of the stress distribution.