Experimental Study of Erodibility in Compacted Cohesive Soils for Embankments

The most common cause of embankments failures is erosion due to water flowing over tops of of them. Specifications and compaction effort used in construction of the embankments affect significantly in erosion rate during overtopping. The objective of this research is investigation the effect of clay percentage، compaction effort and water content on the erodibility of cohesive soils. The soils used consist of sand mixed with Bentonite in proportions varying from 10% to 20% by weight. Soil samples are compacted in the standard compaction mold at different water contents and compaction efforts، then they are tested by a closed conduit in varying discharges and obtain erosion parameters for each of them. The results indicate that the sample compacted at optimum water content creates a structure with the most resistant to erosion. The erodibility of samples compacted dry of optimum water content is less than samples compacted on the wet side of optimum، critical shear stress of wet side of compaction curves is minimum 1. 2 and maximum 1. 6 times dry side. The higher compaction effort at given water content in dry side increases critical shear stress and decreases erosion rate.