Investigation on strength and deformation properties of lateritic clay

Lateritic clay is often used as a construction material for roads in tropical and subtropical areas. However, these materials exhibit high compressibility, high rate of creep, and susceptibility to severe cracking due to swelling and shrinkage behavior. These traits are closely linked to its hydro-mechanical and deformation properties. In this study, firstly, a boundary line between the swelling and compression deformation zone was determined based on the results of wetting tests. This boundary line is crucial for identifying the specific deformation mechanisms observed in unsaturated lateritic clays under varying water conditions. Secondly, an analysis of the relationship between pore size distribution and the soil water retention curve (SWRC) were conducted. A simple bimodal SWRC model, using the normal distribution function, was proposed. Additionally, the strength characteristics of lateritic clay were investigated over a wide suction range. It was observed that the existing strength model significantly underestimated the tested values in the medium to high suction range. To address this, a segmented strength equation was introduced based on unsaturated effective stress analysis. This approach allows enables enhanced predictions of the strength properties of lateritic clay. Altogether, these findings have greatly contributed to a better understanding of the engineering properties of lateritic clay. •Lateritic clay is often used as a construction material for roads.•A boundary line between swelling and compression deformation zone was determined.•The strength characteristics of lateritic clay were investigated.•A segmented strength equation was introduced with good predictive performance.