Experimental Study on Contact Erosion Failure in Pavement Embankment with Dispersive Clay

Abstract

Soft subgrades are not strong enough to provide the required degree of compaction for a pavement embankment’s foundation. Therefore, it is required to treat the subgrade soil or construct a working platform on top of the soft subgrade to ensure proper compaction of the subsequent layers. The constriction sizes of the granular materials used for a working platform are comparatively higher to restrict the erosion of overlying embankment materials. This condition would lead to severe material loss in the embankment layer in cases where the embankment is constructed with dispersive soil, which becomes structurally unstable in wet conditions and appears to disperse in water. This paper investigates the contact erosion failure at the foundation of a pavement embankment constructed with dispersive soil as a result of groundwater fluctuation. Experimental studies were conducted on a laboratory model test apparatus designed to simulate the conditions in the pavement embankment’s foundation. The experimental studies revealed that the magnesium dominant clayey soils also susceptible to contact erosion failure due to soil dispersion. Also, the experimental results show that even a small percentage of dispersive clay particles present in the embankment soil would influence the contact erosion failure.