Geotechnical Assessment of some Clay Deposits in Southwestern Nigeria for use as Sanitary Landfill Liner
Pages : 1061-1067Download PDF
Urbanization cum Industrialization enhance generation of solid wastes that pose different threats to the environment and human health. The potential threat posed by these wastes determine the type of Landfill liner required to safe our aquifers .This study investigates the geotechnical properties of three soils from southwestern Nigeria for their use as liners in landfill. Three samples of clay were collected and subjected to grain size analysis, moisture content, specific gravity, bulk density, atterberg limits, permeability, compaction, shear strength, consolidation, unconfined compressive strength and California bearing ratio tests. The grain size analysis and the atterberg limit, the soil is classified as a clayey material. The percentage of fines ranges from 23-34%. The bulk density ranges from 1.34-1.47g/cm3. The moisture content values are within the range of 0.8-4.2%. The specific gravity ranges from 2.56-2.66. The liquid limit ranged from 27.5%-34.5%, the plastic limit ranged from 15.3%-18.0% and its plasticity index ranged from 11.0%-19.2% which implies that the clay can withstand volumetric shrinkage on drying and exhibit a low to medium swelling potential when wet. Hydraulic conductivity values ranges from 1.46 x 10-7-1.18 x 10-4cm/sec. The compaction test reveals an optimum moisture content (OMC) ranging from 14.0-17.0% and a maximum dry density (MDD) that varied from 1.73-1.8g/cm3. The shear strength values of the samples are within 10-30KN/m2. Coefficient of consolidation and volume of compressibility ranges from 1.0-1.9 x 10-7m2/min and 1.5-2.6 x 10-3m2/KN respectively. Unconfined compressive strength for both cured and uncured samples ranges from 373-420KPa and 100-120KPa respectively. The California Bearing Ratio values for unsoaked test ranges from 53-60% while for soaked test the values ranges from 16-24%. This research work showed that the studied clay were in favour of being used as landfill liner material.
Keywords: Clay Deposit, Landfill liners, Containment, Geotechnical characteristics, Southwestern Nigeria