Geotechnical properties of Ajali Sandstone in Enugu, Nigeria for engineering use

Abstract

Twelve soil samples collected at different intervals from 0.1 meter deep in Onyeama Mine, Enugu State from the Ajali sandstone were subjected to geotechnical analysis (moisture content, sieve analysis, Atterberg’s limits) to determine their suitability for the siting of some engineering structures. The results show that the soils are cohesive at shallow depths (1.8m – 1.0m). It is cohesionless with greater sandy fraction at greater depths. The moisture content values are low and averages 10.65% (from depth 0.00m– 1.8m). For the Atterberg limit; liquid limit ranges from 31% - 36% while the plasticity limit was 25%. On the AASHTO classification and plasticity chart, part of these results show that the top soils at shallow depths (1.8m – 1.0m) are inorganic clays. Consequently, the top inorganic layer needs to be stabilized or excavated and back-filled with more stable materials for engineering structures purposes.