Response of isolated footing on a geogrid reinforced fill and undisturbed peat subgrade soil system

Abstract

The geotechnical behavior of undisturbed peat subgrade within geogrid-reinforced foundation systems remains inadequately understood, despite its high compressibility and engineering complexities. This study conducts a systematic investigation into the bearing capacity and settlement characteristics of an isolated footing on geogrid-reinforced fill over undisturbed peat, utilizing laboratory-scale model tests. Unlike previous studies that rely on disturbed peat samples, this research preserves natural stratification and in-situ response mechanisms, providing a more accurate representation of reinforcement performance. The results demonstrate that geogrid reinforcement enhances bearing capacity by up to 149.7 % and mitigates settlement by 79 %, with optimal reinforcement efficiency achieved at h/B = 0.3. These findings underscore the critical role of geogrid embedment depth, fill thickness, and relative density in optimizing foundation stability. By integrating undisturbed peat in physical modeling, this study bridges the gap between controlled laboratory experiments and real-world geotechnical applications, providing a framework for optimizing geosynthetic reinforcement strategies in highly compressible subgrades and paving the way for more reliable foundation designs in challenging ground conditions.