Expansive Soils: Examining the Critical Parameters Influencing Swelling and Shrinkage

Expansive soils, characterized by high clay mineral content, especially montmorillonite, pose significant challenges in geotechnical engineering due to their large volume changes in response to moisture fluctuations. Prevalent in regions with extreme climates, these soils swell when wet and shrink when dry, creating structural risks for infrastructure. Analysing the shrink-swell behaviour of expansive soils reveals critical factors driving these volume changes and their impacts, particularly in areas where climate variability exacerbates moisture extremes. Examining soil suction, water retention characteristics, and pore size distribution (PSD) uncovers mechanisms influencing swelling-shrinkage cycles. The Water Retention Curve (WRC) illustrates how unsaturated soils manage moisture and demonstrates the influence of soil texture, density, and mineral composition on water retention. Additionally, the effects of compaction and consolidation on PSD reveal how pore structure modifications amplify or mitigate expansive tendencies. Geotechnical parameters, including plasticity index, water content, and dry density, are highlighted as central to understanding soil swelling behaviours. Given the numerous factors influencing soil swelling, it is crucial to conduct studies that identify and evaluate the most significant parameters to improve predictive models and advance the understanding of swelling behaviour in expansive soils.