Geotechnical Properties of Soil for Design and Construction of Foundation from Elebele Town, Bayelsa State, Nigeria

Abstract

The geotechnical properties of soils influence the stability of construction materials and civil engineering structures. This study investigated the geotechnical properties of soil for design and construction of foundation from Elebele Town, Bayelsa State, Nigeria using standard techniques. Results obtained show that the Atterberg limit results reveal that the liquid limit ranges from 64.3% to 96.5%, the plastic limit ranges from 28.9% to 45.6% while the plasticity index values range from 33.7% to 51.3%. The cohesive soils (clays) are highly plastic (CH) in the Unified Soil Classification System (USCS) designation. The natural moisture content ranges from 57.5% to 87.9%. The particle size distribution analysis reveals that the sand is fine to medium to coarse grained and in a medium dense state of compaction and based on its coefficient of uniformity and gradation classifies as poorly graded (SP) by the USCS designation. The moisture content of the sand ranges from 10.2% to 13.5% while the bulk unit weight ranges from 18.8KN/m³ to 20.3 KN/m³. The angle of shearing resistance ranges from 27⁰ to 34⁰. The result of the undrained shear strength of the clay ranges from 15Kpa and 18Kpa. The clay is very soft to soft and exhibit medium to high moisture content. The strength test result indicates a material of low undrained shear strength, the coefficient of consolidation, Cv of the clay soil samples varies between 1.41m²/year and 2.49 m²/year. The coefficient of volume compressibility, Mv, for the same materials varies between 0.667 m²/MN and 6.338 m²/MN, generally indicating clay layers of high to very high compressibility. Raft foundation is best suited for this weak, soft foundation materials.