Geotechnical Properties Of Ajali Sandstone In Anambra Basin

Twelve soil samples were collected at different interval from 0.1 meter deep in Onyeama Mine in Enugu State from the Ajali Sandstone. These were subjected to geotechnical analysis to determine their suitability for the location of some engineering structures. Test carried out on these sample include moisture content, sieve analysis and Atterberg's Limits. Results of these analysis show that the soil are cohesive at shallow depths (1.8m - 1.0m) and cohesionless and sandy fraction at greater depths (0.8m - 0.0m). The moisture content ranges between 9.44% to 11.86% averaging 10.65% (from depth 1.8m - 1.1m). It ranges from 8.83% - 12.71%, depth 1.0m - 0.6m, it ranges from 8.17% - 14.60%, and depth 0.5m - 0.3m ranges from 7.88% - 13.10%. These show low values. For the Atterberg limit, liquid limit and plastic limit, plasticity indices of the cohesive portion ranges between 26.9% - 18.3% and 3.5% - 10.6% respectively. AASHTO classification and a plasticity chart part of these results show that the top soils at shollow depths (1.8m - 1.0m) are inorganic clays. Thus, it is important that the top inorganic layer be stabilized or excavated and back filled with more stable material.