Stability Modeling of Sand-Gravel Fill Zoned Embankment

Abstract

When an embankment is built above the natural ground and compacted, depending on the fill
materials employed, it acts as a base for roadways and railway lines. This study sought to
determine the effectiveness of sand and gravel as fill materials in the building of zoned
embankments. To do this, slope stability analysis was performed using GeoStudio's finite element
programme Slope/W and the Morgenstern Price slice technique. Computations and analysis show
that for a zoned embankment of sand and gravel-all in, sand and 19.0mm gravel, sand and 13.20
mm gravel, sand and 9.50 mm gravel and sand and 6.70mm gravel gave factors of safety of 1.068,
1.12, 1.13, 1.1 and 1.17 at slope failures of 54.46, 57.99, 48.58, 53.13 and 48.58 respectively. In
its analysis considering steady seepage, an embankment zoned with sand and gravel fills will
prove safe as far as an angle of 12.99 degrees which gives a factor of safety of 1.649 for each
gravel size zoned with sand. Hence this research has not just proven how effective sand and gravel
fill material can be in the construction of zoned embankment, but to what extent they can slope
before failure occurs using different particle sizes of gravel with sand as fill.