Collapse and Swell of Lime Stabilized Expansive Clays in Void Ratio–Moisture Ratio–Net Stress Space

Abstract

The swell-collapse mechanism of residual basaltic clay in both untreated and stabilized with lime conditions was investigated. For treated specimens, the optimum lime content (OLC) was found based on swell potential reduction. Swelling and collapse potential were investigated using the virgin compaction surface, which is the backbone of the Monash-Peradeniya-Kodikara (MPK) framework. The suitability of the MPK was examined by applying different state paths. The swelling and collapse potentials were tested under a wide range of moisture contents and stress levels, with attention given to the effect of stress history and operational stress. Test results indicated that for the untreated and lime-treated clay (at OLC), the behavior of soil during loading, unloading, and wetting closely followed the MPK framework. However, the MPK did not extend to specimens with very low moisture content wetted under low stresses, and, consequently, a new improved model was suggested. Furthermore, a new method for predicting the swelling and collapse potential was proposed using the virgin compaction surface.