APPLICATION OF FINITE ELEMENT METHOD FOR THE ASSESSMENT AND COMPARATIVE ANALYSIS OF EMBANKMENT CONSOLIDATION

Abstract

The long-term performance of highway embankments constructed on compressible soils is significantly influenced by consolidation settlement and deformation characteristics of the underlying foundation soils. Conventional analytical approaches such as Terzaghi’s one-dimensional consolidation theory are widely used for settlement prediction; however, these methods are limited in representing complex subsurface conditions and realistic field behavior. This study therefore assessed embankment consolidation behavior using both Terzaghi’s analytical method and the Finite Element Method (FEM) implemented in PLAXIS 2D within the Ewu Hill section of the Benin–Auchi Expressway. Representative geotechnical datasets comprising moisture content, Atterberg limits, permeability, compression index, coefficient of consolidation, cohesion, and friction angle were obtained from published geotechnical investigations and documented embankment studies within humid tropical environments of Southern Nigeria. Terzaghi’s analytical consolidation procedure was applied to estimate settlement magnitude and consolidation rate, while FEM simulation was conducted using coupled hydro-mechanical analysis in PLAXIS 2D to evaluate stress redistribution, pore water pressure dissipation, deformation behavior, and long-term embankment performance. The results revealed that settlement increased progressively with time due to gradual dissipation of excess pore water pressure within the embankment foundation soils. The FEM simulation predicted higher and more realistic settlement values compared to the analytical method due to incorporation of layered soil conditions, nonlinear soil behavior, multidirectional drainage, and realistic stress interaction. The study further established that moisture content, permeability, compressibility, and shear strength parameters significantly influenced embankment performance and long-term settlement susceptibility. The FEM analysis also demonstrated that maximum settlement occurred beneath the embankment centerline where stress concentration was highest. The study concluded that FEM implemented in PLAXIS 2D provides more comprehensive and reliable assessment of embankment consolidation behavior under complex geotechnical conditions compared to simplified analytical approaches. The findings contribute to improved highway embankment design, settlement prediction, and long-term geotechnical performance evaluation within humid tropical environments.