Compaction and Consolidation Characteristics of A-7-6 Soil

Abstract

This study presents an investigation of the compaction and consolidation characteristics of black clay soil, which belongs to A – 7 – 6 soil class. The soil samples were collected at 0.5, 1.0, 1.5 and 2.0 metres from selected active pits of clay deposits in Bako, a village in Gwagwalada Area Council of the Federal Capital Territory, Abuja, Nigeria. Compaction and consolidation characteristics of collected samples under axial and compressive loads were investigated. Maximum dry density and optimum moisture content as well as recompression/compression index were calculated from the compaction and consolidation results respectively. The values of compaction and consolidation characteristics from the experimental results were then compared with those obtained using different empirical correlations from literature. The Liquid limit for samples passing through sieve No 200 (0.075 mm) ranged 64.29 to 81.67 % while plasticity index is 34.29 %. The compression index (Cc) values vary slightly with the applied compaction energy levels. The modified energy level recorded the highest Cc of 0.2989 which reduces to 0.2823 at the Standard proctor compaction energy level. The West Africa energy level gave a value of 0.227. The lowest value of 0.1531 was obtained for the Reduced standard proctor compaction energy level. The soils recompression index (Cr) varies from 0.0529 at the Standard proctor compaction energy level to 0.0229 at the Reduced Standard proctor energy level while its value was maintained at 0.0059 for both the West Africa and Modified energy levels.