Axisymmetric numerical modeling of a unit cell in geosynthetic-reinforced, column-supported embankments

Abstract

Rational design of geosynthetic-reinforced, column-supported embankments requires realistic estimates of the portion of the embankment load that acts vertically downward on the geosynthetic in the area underlain by the foundation soil located between columns. This vertical load can then be used to calculate the strain and tension that develops in the plane of the geosynthetic reinforcement. Several simplified methods are available for calculating the vertical load acting on the geosynthetic, but these methods produce dramatically different results, and there is not agreement regarding which method produces the best estimates. Axisymmetric numerical modeling provides an alternative approach for determining the vertical stresses that develop in the embankment and act on the geosynthetic reinforcement. In this research, axisymmetric numerical modeling is verified against: (1) instrumentation data from a full-scale column-supported test embankment, albeit without geosynthetic reinforcement, at the I-95/Route 1 Interchange project in Virginia, USA; (2) an analytic solution for a disk of membrane material that is pinned at its outer edge and subject to a vertical stress; (3) instrumentation data from a pilot-scale test of a geosynthetic-reinforced, column-supported embankment conducted at the University of Kassel in Germany; and (4) three-dimensional numerical analyses. The results demonstrate that drained axisymmetric numerical analyses using a mesh of linear elastic zones to represent the geosynthetic reinforcement produce results in good agreement with instrumentation data, the analytic solution, and three-dimensional analyses.