Constitutive model of lime-stabilized laterite considering curing time and softening characteristics

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.