Load transfer mechanism in geosynthetic reinforced column-supported embankments

The load transfer mechanism of geosynthetic reinforced column-supported embankments is governed predominantly by the soil arching mechanism. A large number of studies found in the literature examine the arching over a rectangular arrangement of columns. However, the load transfer mechanism over a triangular arrangement is not widely investigated. This paper investigates the mechanism of soil arching in an embankment supported by columns in a triangular grid, using 3D numerical models. The column efficacy and settlements were compared between triangular and square grids. A visual boundary of the soil arch above the triangular grid of columns was developed based on the 3D modelling. A parametric study was carried out to investigate the influence of geosynthetic reinforcement, mechanical properties and height of embankment, and strength and configuration of columns (spacing and diameter) on the column efficacy and arch shape. Results show that columns experienced lower settlements and the geosynthetic reinforcement was less effective when the column arrangement was triangular, compared to a square arrangement. The most influential parameter on the column efficacy is column spacing and the second is diameter. Both height and width of the soil arches were changed with column spacing. Only the width of the arch was changed with column diameter.