Strain localization in lime treated expansive soil under compression loading using digital image correlation

Stabilizing expansive soils using lime is a conventional technique to improve their shear strength and volume change characteristics. Lime treated soils are often used in the con-struction of highway/railway subgrades and embankments. However, the crystalline pozzolanic products formed due to lime addition give rise to brittleness in the soil mass which results in local strain concentration ultimately leading to sudden catastrophic failures. Therefore, in the current investigation, a comprehensive study of strain localization response of a large cylindrical speci-men (100 mm diameter and 200 mm height) subjected to uniaxial compression was performed. An automated digital image acquisition system was employed for continuous monitoring of front and rear surface of the specimen. Digital image correlation (DIC) technique was used to charac-terise and quantify the strain localization occurring over the specimen surface. The localized strains as high as three times the global strain values were observed in some zones of the speci-men.