Settlement analysis of ground treated with granular piles using natural and recycled aggregates

Abstract

Scarce land availability forces humans to build on soft soils, prone to long-term deformation and lacking sufficient shear strength, resulting in potential structural damage. Granular piles (GPs) are suitable for treating soft clay, providing increased load-bearing capacity, reduced settlements, faster consolidation, liquefaction risk elimination, and improved stability for natural slopes and embankments. Traditionally natural aggregates are used as granular material in pile construction, whereas the present study aims to analyze the effect of replacing natural aggregates with some recycled waste aggregates. The main objective of the present study is to numerically investigate the settlement resistance and load-carrying capacity of weak soils by incorporating granular piles made of unconventional aggregates. This numerical analysis considers various granular materials for piles, including natural aggregates (NA), crushed concrete (CC), crushed brick (CB), and industrial waste aggregates like crushed marble (CM) and crushed sandstone (CS). According to the findings of the current study, the use of crushed concrete (CC), crushed brick (CB), and industrial waste aggregates such as crushed marble (CM) and crushed sandstone (CS) in the formation of granular piles led to a notable enhancement in the settlement characteristics and bearing capacity of soft soils. In the current study, some experimental models of locally available sandy soil treated with granular piles are prepared and tested in California bearing ratio (CBR) moulds to investigate their settlement behavior. Granular pile models are prepared of natural & recycled aggregates (CC), and the effect of incorporating cementing agents like - cement and flyash on the settlement behavior of reinforced ground is also investigated. Experimentally, the sandy soil treated with granular piles made of natural and recycled aggregates shows higher resistance towards settlement compared to untreated soil. The resistance towards settlement increases marginally with the incorporation of cementing agents. The optimum value of CBR (80%) is observed for sandy soil treated with a granular pile of natural aggregates with cementing material (3% cement + 6% fly ash) cured for 7 days (TNCF7).