This study presents a comprehensive investigation into the mechanical properties of lime-stabilized lateritic soil, with a focus on developing an improved constitutive model that incorporates both curing time and strain-softening effects. Current constitutive models fail to accurately capture the stress-strain behavior of lime-stabilized soils, particularly over extended curing periods. To address this, unconfined compressive strength (UCS) tests were conducted using lime contents of 0%, 1%, 3%, 5%, 7%, 9%, and 11% revealing that 7% lime content optimally enhances the compressive strength of the soil by 1202.66% compared to untreated soil. Triaxial consolidated-drained tests were then performed with the optimal 7% lime content, considering curing times of 3, 7, 14, and 28 days under confining pressures of 100 kPa, 200 kPa, 300 kPa, and 400 kPa. The results demonstrated that the shear strength, cohesion, internal friction angle, and initial tangent modulus of lime-stabilized lateritic soil increased with longer curing times and higher confining pressures. These findings were integrated into a re-modified Duncan-Chang model, which incorporates both strain softening and curing time as key factors. The revised model was validated through comparisons with experimental data, achieving an average relative error of 2.12% at 7 days, 1.46% at 14 days, and 17.55% at 28 days. This validation demonstrates the model's ability to accurately predict the stress-strain behavior of lime-stabilized lateritic soil under different curing conditions. The novelty of this research lies in the successful integration of curing time and strain-softening effects into the Duncan-Chang model, providing a more accurate tool for predicting the long-term mechanical performance of stabilized soils. The findings have significant implications for engineering applications, particularly in the context of soil stabilization for infrastructure projects in tropical and subtropical regions.

This study investigates the influence of age on the mechanical properties of lime-modified dispersed soils through consolidation undrained triaxial tests conducted at various age (t) and lime content (a). Empirical equations for Duncan-Chang model parameters K, n, c, and phi incorporating the age factor were established based on experimental results, focusing on lime modification at 2% content. The stress-strain curves of dispersed soils exhibit strain-hardening characteristics, with stress levels increasing notably with age, displaying significant variation between short and long durations. Conversely, the stress-strain curve for lime-modified dispersed soil at 2% content shows strain-softening behavior. Age exerts a substantial influence on model parameters K, n, c, and phi of the Duncan-Chang model, with a minor impact on Rf. The modified model demonstrates a strong fit to stress-strain curves of lime-modified dispersed soil before reaching failure, validated against experimental data at age of 14 days and 90 days. Importantly, the modified model accurately predicts stress-strain relationships for modified soils over extended age beyond 28 days, providing meaningful insights for the long-term stability assessment of soil-modified structures.