GEOTECHNICAL PROPERTIES OF SAND DERIVED FROM AWDAW RIVER CHANNEL OKO-AMAOKPALA AREA ANAMBRA BASIN, SOUTHEASTERN NIGERIA

Abstract

The alarming rate of failure and collapse of infrastructures in Nigeria is statistically notable setbacks to economic growth and constitute major causes of loss of lives and properties. Five (5) sand samples, named Oko samples 1-5, were collected from Awdaw River Channel at Oko-Amaokpala area, Anambra Basin. The samples were prepared and subjected to geotechnical tests such as Atterberg limits (liquid limits, LL, Plastic limits, PL, Plasticity index, PI, shrinkage limit); Compaction test (Optimum Moisture Content (OMC), Maximum Dry Density), Grain size distribution, Triaxial compression, Natural Moisture Content and Specific Gravity, using standard methods. The result shows that natural moisture content varies from 11.4% to 13.0%, specific gravity ranged from 2.56mg/cm³ to 2.67mg/cm³. The Particle size distribution revealed gravel content (0%), sand (81.7% - 89%) and fines (11.0% - 18.3%). The Atterberg limit test showed liquid limit (LL) that ranged from 27.0% to 35%. Plastic limit (PL), ranged from 11.0% to 17%. Similarly, the angle of shearing resistance, (ɸ), ranged from 26⁰ to 31⁰ and effective cohesion ranged from 10kN/m² to 16KN/m². The shear stress (Ʈ) values ranged from 258.81KN/m² to 338.00KN/m² with pressures of 100, 200, and 300KN/m². The compaction test revealed that void spaces will contain lots of air and will require good compactive effort to improve its engineering properties. The predominance of sand would guarantee high performance when used in making sandscrete blocks and in road construction works. Generally, the sand is good material for building construction, albeit, not good to be used as base course material in highway construction.