Abstract

The study dealt with base and sub materials investigations of the soils used for embankment construction of Kali dam Aliero, north western Nigeria, to classify and examine their geotechnical behavior and proportionality to the dam's failure. Disturbed soil samples were collected from selected
locations, these samples were analyzed for their physical characteristics which include soil consistency, grains size distribution, Plasticity Index (PI), Coefficient of Permeability (CP), Maximum Dry Density (MDD), and Optimum Moisture Content (OMC) and moisture-density relationship.
Analysis of the engineering properties of rocks revealed moderate to good index of the soil samples collected, The presence of impermeable soils is shown by the coefficient of permeability, which indicates that certain samples have low permeability while others have intermediate permeability.
Investigation revealed that, the site soil materials are suitable for dam sitting. Furthermore, the possible causes of the failed portion of the dam are as a result of deviation from the specified or recommended standards and improper foundation.

Key words: Sub material, sub-base, Soil Consistency, Coefficient of Permeability, Kali Dam, Aliero