PERMEABILITY AND CONSOLIDATION CHARACTERISTICS OF COMPACTED LATERITE SOILS IN AKURE AREA, SOUTHWESTERN NIGERIA.

Abstract

The permeability and consolidation characteristics of laterites soils in Akure, southwestern Nigeria were investigated with a view to determine their suitability for use as barrier or liners in landfills. The specific aim of this research is to quantitatively and qualitatively determine the permeability and consolidation characteristics of compacted laterite soils in Akure area, their index properties, influence on local geology, moisture content at different energy levels. The main purpose of liners is to safely contain waste and control leachate to mitigate ground and groundwater pollution and the protection of public health. In other to achieve the aforementioned objectives, there is need to put in place barriers (or liners) that will help achieve fail safe conditions required of landfills. A total of twenty-five text samples were collected from sample pits at the accumulation zone, Mineralogically the outcrops composed of feldspar, biotite and quartz at different proportion. The geology, petrography and geotechnical properties of these rocks have been studied; the mechanical sieve analysis is adopted to determine the particle size distribution. Specific gravity values for the soil samples ranges from 2.502 to 2.782 with an average value of 2.667, results of compaction were plotted as moisture-density curves, falling head permeability method of testing was adopted in the experimentation coefficient of permeability ranged from 2.38 x 10-4 to 6.53 x 10 -4, one-dimensional consolidation test carried out in this research is presented in Table 4.7. values of the void ratio ranges from 0.242 to 0.753; Coefficient of volume compressibility ranges from 0.07825 to 0.53534MPa-1 ; the coefficient of compressibility value ranges from 0.10306 to 0.8855MPa-1. The results showed that Laterite in their normal state cannot be used as liners or barriers but when compacted at different moisture content and different energy levels they can be used to solve the problem of barriers in waste disposal site.