Geofoam-enhanced soft embankments with a load distribution slab for improved pavement performance: A 3D numerical analysis

Constructing pavement on soft embankments poses significant challenges due to unpredictable lateral movement, excessive settlement, and poor shear resistance. Engineers often employ geotextile‐reinforced columns (GRCs) to mitigate these issues for pavement support. However, granular columns in soft soils may suffer from inadequate lateral confining pressure in their upper sections. To overcome this, high‐strength geofoam is deployed to confine the columns, and when paired with a load distribution slab (LDS), overall stability improves markedly. This method effectively curbs settlement, lateral displacement, and deflection by harnessing tensile stress. This study developed a hypothetical embankment model supported by GRCs with an underlying geofoam layer and LDS, subjected to 12, 33, and 66 kPa loading levels following the cyclic stress protocol defined in AASHTO T 307-17 (“Standard Method of Test for Determining the Resilient Modulus of Soils and Aggregate-Base Course Materials”). Using Continuum Fast Lagrangian Analysis in 3D for numerical analysis, we found that embankments without an LDS settled by 55 mm at 12 kPa within 10 months, increasing to 92 mm after 35 months. Under 33 and 66 kPa loads, immediate settlements reached 121 and 168 mm, respectively. Conversely, the system incorporating geofoam and an LDS maintained an average settlement of only 11 mm across all stress conditions. These results demonstrate that integrating an LDS yields a more uniform stress distribution, significantly reducing settlement and deflection while enhancing pavement stiffness on soft embankments. In summary, using geofoam and LDS offers a promising solution for constructing durable pavements on soft embankments. These findings provide a robust framework for enhancing pavement performance by systematically reinforcing soft embankments.