Filter with simple but effective job is one of the principal parts in an embankment dam which is able to immune the dam against erosion, prevent water escape and seal unfavorable cracks that may occur through the impermeable core. Geotechnical properties of granular materials (filters) from two States in the Southwestern Nigeria were presented in this paper, using locally and commercially sourced aggregates. Nine granular soil samples were collected: peat and sharp sands from two borrow pits; gutter and river sands with gravel from Ogbomoso, Oyo State; quarry dust and granite from Ministry of Transport Osogbo, Osun State. Samples were subjected to the following laboratory tests: Particle size analysis, Atterberg limit, Compaction, Specific Gravity, Constant Head Permeability. Results of the particle size analysis passing sieve No. 200 for peat, sharp, gutter, and river sands, with gravel, quarry dust and granite were 2.94%, 1.12%, 0.81%, 1.35%, 3.13%, 0.68%, 0.58%, 5.93% and 0.32% respectively while those passing through sieve No. 4 are 97.92%, 89.91%, 97.22%, 95.90%, 26.76%, 88.05%, 96.50%, 97.93% and 24.71% respectively. The plasticity Index were 5.13%, 6.94%, 8.17%, 6.11%, 8.37%, 0.59%, 2.47%, 2.48% and 10.76% respectively. Optimum moisture content and maximum dry density were (5.11% ;1830 Kg/m3) , (6.57% ;1960 Kg/m3) , (12.36% ;1940 Kg/m3) , (8.57% ;1930 Kg/m3) , (8.73% ;2080 Kg/m3) , (11.86% ;2150 Kg/m3) , (7.73% ;1820 Kg/m3) , (6.10% ;1840 Kg/m3) and (6.29% ;1720 Kg/m3) respectively. Specific gravities of the samples were 2.73, 2.70, 2.75, 2.80, 3.02, 2.84, 2.85, 2.82 and 3.98 respectively. Permeability coefficients were 3.54 × 10-5cm/s, 3.14 × 10-5cm/s, 3.59 × 10-5cm/s, 3.64 × 10-5cm/s, 2.59 × 10-5cm/s, 3.09 × 10-5cm/s, 2.87 × 10-5cm/s, 2.78 × 10-5cm/s respectively. The locally sourced materials are adequate and suitable to serve as filter materials, with relatively low cost compared to commercially sourced aggregates
Keywords: : Erosion, Filters, Geotechnical Properties, Granular Material, Locally Sourced
