Numerical modeling of the effectiveness of recycled aggregates in reinforcing soft soil with granular columns

Abstract

In recent years, the civil engineering field has increasingly focused on recycled aggregates due to the dwindling availability of natural aggregates and the high carbon footprint associated with their extraction and use. The use of recycled aggregates aims to decrease energy consumption and lessen the environmental impact caused by construction waste. This study illustrates the value of utilizing recycled aggregate materials for soil reinforcement and demonstrates their efficiency compared to natural aggregates. The research employs several numerical simulations carried out using PLAXIS 3D, a finite element software renowned for its advanced modeling capabilities. These simulations leverage the Mohr-Coulomb failure criteria alongside an elastic-perfectly plastic behavior model to assess the performance of various materials under different conditions. Specifically, the study investigates three types of granular columns—Ordinary Stone Columns (OSC), Sand-Fiber Mix (SFM), and Recycled Aggregate Porous Concrete Piles (RAPP)—to reinforce a unit cell model of soft soil under failure loading scenarios. Detailed analysis reveals that recycled aggregate columns exhibit a significantly higher bearing capacity, showing an improvement of up to three times that of columns made with natural aggregates. This superior performance is attributed to the enhanced mechanical properties and better load distribution capabilities of the recycled aggregates. The results are presented through load-settlement curves, which provide a clear visualization of the effectiveness of each type of granular column. Furthermore, the study highlights the practical implications of using recycled aggregates in soil reinforcement projects. The substantial improvements in bearing capacity demonstrated by the recycled aggregate columns underscore their potential as a viable and sustainable alternative to natural aggregates in various geotechnical applications.