On yield stress of compacted clays

Artificial compaction is a commonly practiced ground improvement technique around the world. Yield stress is an important parameter to quantify and analyze the strength and compressibility behavior of the artificially compacted clays; such materials are indeed of practical significance in various projects, e.g., engineered landfills, clay liners, etc. The present study aims to investigate the influence of different geotechnical characteristics of compacted clays of wide plasticity range on the compaction induced yield stress, and also to develop the correlational models to quickly predict the yield stress. Three natural clayey soil samples of different geotechnical properties were collected from different sites; 27 more samples of varying index properties were prepared by mixing bentonite with natural soil samples at varying rates. Series of one-dimensional consolidation tests were performed to determine compressibility parameters like yield stress, compression index, and coefficient of volume compressibility. Atterberg’s limits, grain size, compaction characteristics, and compressibility have a significant influence on the compaction induced yield stress. Predictive models of yield stress are also developed by using the plasticity index, optimum water content, and maximum dry unit weight as independent variables. Moreover, developed models are validated based on the independent data.