Investigation of geotechnical properties of soil samples in Isu-Njaba Imo State

The properties of the geotechnical characteristics of soil samples from Isu-Njaba borrow pit was carried out in this study. Ten soil samples from the depth of 3m were taken from the pit at day1, day7 and day14 respectively. The tests carried out on the soil samples include sieve analysis, natural moisture content, Atterberg limit, compaction and California bearing ratio tests in line with standards. From the results, the fine soil content is 4.19%, and the soil samples contain more of sand and gravel and are uniformly graded. Thus the soil is classified as A-2-4 soil in line with AASHTO standard of soil classification. The obtained liquid limit is 38.02%, plastic limit of 27.53% and plasticity index of 10.49%. The results from the test on compaction showed the maximum dry density to be 1.56 Mg/m and optimum moisture content as 14.30%. The values of the California bearing ratio for the non-soaked soil is 20.64%, and 12.63% for the soaked soil. The study showed that the soil samples from Isu-Njaba borrow-pit could be applied as materials for sub grade, sub base and base purposes, as most of the properties meet the specifications of the Federal Ministry of Works and Housing guidelines for road construction.