Macromechanics, microstructure and particle contact model of artificially cemented laterite

Abstract

In this paper, the research is based on iron hydroxide colloids that combine loose kaolin clay media to form artificial laterite samples. A method and device for the preparation of colloids have been developed. The compressive strength test method is used to explore the regularity and mechanism of free iron oxides which in the process of the formation and strength increase of laterite structure. X-ray diffraction (XRD), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR) were used to study the mineral composition of the laterite, the cementation of microscopic aggregates of the particles, and the changes in the internal porosity of the laterite. The results show that the free iron oxide can improve the macro-mechanical properties of laterite. The iron morphology has a tendency to change from colloid to hematite and goethite. It is found that the free iron oxide aggregated in the space or on the surface of clay particles. Distribution; gel particles were found to fill the pores of laterite particles or aggregates by nuclear magnetic resonance experiments, indicating that the changes in the mechanical strength of laterite are mainly due to the content of free iron oxide, the formation of free iron oxide, the connection of cementing iron and the distribution of iron. Based on the SEM results, a contact model of laterite particles that can reflect the macro-mechanical failure behavior of soil samples is established.