Effect of stress history on stress-strain and volumetric response of laterite soil under undrained and drained conditions

Laterite soils are tropically weathered residual soils containing significant iron content and are known for their highly dispersive nature. Laterite soils with high fines content dominated by silt fraction disperse easily in the presence of water due to weak binding forces. Thus, the soil particles get washed away with water creating local instabilities thereby triggering slope failures. Previous research on laterite soil has been limited to the basic geotechnical properties including grain size distribution (GSD), specific gravity (Gs), permeability, compaction, etc. The laterite soils are vulnerable to severe erosion, thereby inducing over consolidation in the soil and affecting its geotechnical behaviour. The effect of stress history on stress–strain and volumetric behaviour of laterite soil remains unexplored. In the current study, an experimental study was conducted on yellow laterite soil collected from Gosikhurd dam (Maharashtra, India) to evaluate its shear strength behaviour. A series of isotropically consolidated undrained and drained triaxial tests were performed under deformation-controlled triaxial testing conditions at different over consolidation ratio (OCR = 1, 2, 5, and 10). The results indicated significant increase in normalized shear strength, decrease in excess pore water pressure, and volumetric strain with increasing OCR.