Performance evaluation of lightweight clay-air foam embankment on soft Bangkok clay: A full-scale test and 3D numerical analysis

Abstract

This study investigates the performance of a lightweight clay-air foam embankment on soft Bangkok clay through a full-scale test and 3D numerical analysis using PLAXIS 3D. The embankment’s behavior was evaluated in terms of settlement, lateral movement, and earth pressure, with field data compared to numerical predictions. At an embankment height of 2.5 m, the maximum observed settlement was 83 mm, while computed values were overpredicted by 0.5–10%. The maximum lateral movement was 3.6 mm, with numerical predictions overestimating by 9%. Earth pressure measurements showed a peak of 25 kPa, slightly lower than the theoretical 33 kPa, with computed values overpredicted by 18%. A comparison with conventional embankments revealed significantly improved performance using lightweight materials. The traditional embankment exhibited a maximum settlement of 1089 mm, 12.6 times higher than the lightweight embankment. The lateral movement reached 116 mm for the conventional embankment, compared to 3.6 mm for the lightweight embankment. The lightweight embankment shows a maximum earth pressure of approximately 30 kPa, whereas the conventional embankment reaches around 80 kPa, indicating a 2.7 times reduction in stress for the lightweight embankment. Furthermore, the factor of safety was significantly higher for the lightweight embankment (7.28) than for the conventional one (1.13), demonstrating its superior stability. These results highlight the effectiveness of lightweight materials in reducing settlement, lateral movement, and earth pressure, offering a practical solution for improving embankment sscheility on soft soils.