Soft Soil Improvement with Encased Granular Piles Composed of Aggregates and Tire Chips Mixture: Experimental and Numerical Studies

Abstract

This study highlights a novel approach to solving two severe challenges in geotechnical engineering and environmental sustainability. Soft soils, characterized by low shear strength, high compressibility, and poor drainage, require improvement for various construction applications. Nevertheless, the global accumulation of scrap tires has raised serious environmental problems. In response, this study investigates an effective solution by utilizing waste tires to enhance soft soil properties. This research evaluates the optimum mix proportion of aggregates and recycled tire chips and the influence of Combi-grid encasement on the granular piles in terms of ultimate load intensity and bulging behaviour. Recycled tire chips are introduced as a sustainable alternative to traditional aggregates, and granular piles are encased with Combi-grid in various configurations, including vertical, horizontal, and combined encasements with three different spacing. Key findings reveal that the efficiency of ordinary granular piles (OGP) closely approached unity with up to 25% tire chips content, while vertically encased granular piles exhibited efficiencies exceeding unity with up to 100% tire chips content. This study comprehends the optimum tire chip content replacement for aggregates as 25% by weight, equivalent to 44% by volume, offering a cost-effective and environmentally friendly solution. Furthermore, the ultimate load intensity of vertically encased granular piles, horizontal discs at a spacing of 0.25D, and combined encasement at a spacing of 0.25D exhibited remarkable increases of 220.8%, 318.8%, and 414.7%, respectively, compared to ordinary granular piles (OGP). The experimental results are compared with FEM validation using PLAXIS 3D. In conclusion, this study presents an innovative and sustainable approach to enhance soft soil properties by incorporating waste tire chips. © The Author(s), under exclusive licence to Shiraz University 2023.