ABSTRACT

The main aim and objective of the project is to evaluate the foundation soils along atan-agbara road as highway subgrade and sub-base material, to determine the geotechnical basis (if any) for the observed failure cases as studied. The methodology stage involves; Field investigation which entails Desk study stage and Reconnaissance survey and sampling. The samples were collected at different depths from the burrow pit in the study area, naming it TA, TB and TC. This samples are then taken to the laboratory for analysis for determination of specific gravity, grain size distribution,consistency limit test, moisture density relationship and California bearing ratio. The result for the specific gravity which in various depth gave the value above the maximum value which is 2.60. TA, TB ,TC has range of 2.60-2.62 and the average of 2.60 which makes it a good soil in terms of specific gravity. The plasticity index of the soil sample shows that the consistency limit of the soil is good since it has lower value than 17%. The CBR result were less than the required value of 30% and 80% for both the soaked and unsoaked value for sub-base or sub-grade material .The grain size analysis shows that the sample have fine grain particle about 35% which is the required percentage for sub grade . the result for linear shrinkage shows that the shrinkage level of the samples are less than 8% making it a good soil in terms of shrinkage level.