ANALYSIS OF FOUNDATION SETTELEMENT ON FINE GRAINED SOIL (CLAYEY SOIL) IN BENIN CITY, EDO STATE, NIGERIA
Faculty
Department
Year of Publication
Keyword
Publication Type
Abstract
The study was carried out to analyze the settlement behaviors of fine-grained soils-that is, clayey soils-in Benin City, Nigeria, with a view to understanding their geotechnical
characteristics and compressibility under loads. Justification for this research lies in the
frequent structural failures and foundation instabilities observed in clayey sub-soils
across the region Various soil samples collected from the University of Benin and environs were tested for their physical and engineering properties in the laboratory. Standard tests such as moisture content, specific gravity, particle size distribution, Atterberg limits, and
consolidation, in line with ASTM and BS standards, were carried out to study soils' compressibility and settlement behaviors under applied loads. The natural moisture content of the soils varied between 18.6% and 22.4%, while the average specific gravity was 2.57. In addition, the Atterberg limits gave a liquid limit of 38-42%, plastic limit of 22-23%, and plasticity index of 16-19%, classifying the soils as
inorganic clays of low to medium plasticity CL under the USCS and A-7-6 under
AASHTO. More than 50% of soil particles passed the 0.075 mm sieve, which confirms
fine-grained, cohesive soils that are characteristic of the Benin Formation. The results of
the consolidation (oedometer) test show that settlement increases with applied pressure
between 12.5 kPa and 250 kPa, whereas the coefficient of volume compressibility, Mv, decreases from 0.1× 10 −3 and 1.0× 10 −3 m2 /kN, indicating moderate to high compressibility. Generally, these soils are characterized by moderate plasticity, low permeability, and high settlement potential; hence, foundation designs should consider soil stabilization, preloading, or raft and pile foundations, with adequate drainage control to ensure long-term stability
characteristics and compressibility under loads. Justification for this research lies in the
frequent structural failures and foundation instabilities observed in clayey sub-soils
across the region Various soil samples collected from the University of Benin and environs were tested for their physical and engineering properties in the laboratory. Standard tests such as moisture content, specific gravity, particle size distribution, Atterberg limits, and
consolidation, in line with ASTM and BS standards, were carried out to study soils' compressibility and settlement behaviors under applied loads. The natural moisture content of the soils varied between 18.6% and 22.4%, while the average specific gravity was 2.57. In addition, the Atterberg limits gave a liquid limit of 38-42%, plastic limit of 22-23%, and plasticity index of 16-19%, classifying the soils as
inorganic clays of low to medium plasticity CL under the USCS and A-7-6 under
AASHTO. More than 50% of soil particles passed the 0.075 mm sieve, which confirms
fine-grained, cohesive soils that are characteristic of the Benin Formation. The results of
the consolidation (oedometer) test show that settlement increases with applied pressure
between 12.5 kPa and 250 kPa, whereas the coefficient of volume compressibility, Mv, decreases from 0.1× 10 −3 and 1.0× 10 −3 m2 /kN, indicating moderate to high compressibility. Generally, these soils are characterized by moderate plasticity, low permeability, and high settlement potential; hence, foundation designs should consider soil stabilization, preloading, or raft and pile foundations, with adequate drainage control to ensure long-term stability
Supervisor(s)
co-supervisor