Numerical Parametric Study of Strip Footing on Reinforced Embankment Soils

Abstract

Finite element analyses were conducted to assess the benefits of reinforcing embankment soil of low to medium plasticity with geogrids beneath a strip footing from the perspective of the ultimate bearing capacity and footing settlement. The embankment soil was modeled with the Drucker-Prager constitutive model, and the soil-geogrid interaction was modeled by the Coulomb friction model. The finite element model was verified first by laboratory model tests; it was then used to analyze the strip footing sitting on the reinforced soil to seek an optimum reinforcement design. To this end, several geogrid-reinforcement design parameters–including effective reinforcing depth, vertical spacing between reinforcement layers, geogrid stiffness, soil-geogrid interaction coefficient, depth (top spacing) of first geogrid layer, footing embedment, and footing width–were investigated. The results of this study showed that the effective reinforcement depth was approximately 1.5 times the footing width, and an optimum depth of first reinforcement layer existed where the highest bearing capacity could be achieved. The influence of other design parameters on footing's bearing capacity and settlement was also analyzed.