Baseline Geo-Engineering Dataset and Parameters’ Empirical Modeling for Civil Engineering Construction in Okeigbo, Southwestern Nigeria

Authors : Falowo Olumuyiwa OLUSOLA, Olorunda OLUWAFEMI, Ayetoro AYODEJI

Pages : 182-207

View : 19 | Download : 21

Publication Date : 2023-08-30

Article Type : Research Paper

Abstract :This study deals with development subsoil geoengineering dataset and modeling of parameters in Okeigbo area of Ondo State, Southwestern Nigeria. The study employed geophysical methods, geotechnical survey, hydrogeological, and laboratory analysis. Findings revealed the subsoil to be clayey with low compressibility and plasticity. The clay mineral group is dominantly illite-montmorrilonite, of low activity insert ignore into journalissuearticles values(0.36);, and hydraulic conductivity of 3.67E-08 cm/s, while the plasticity index is 23.4 %. The depth to groundwater ranged from 2.2 m insert ignore into journalissuearticles values(in well); – 18 m insert ignore into journalissuearticles values(in borehole);. The depth to basement rock is between 8.2 – 31.5 m insert ignore into journalissuearticles values(avg. 20.9 m);, indicating a moderate to deep weathering profile, able to support burial of engineering utilities such as mast, transformer, gadgets. In regard to pavement construction, the soils are unsuitable for subgrade, base and sub-base courses with CBR less than 7% and GI of 14 insert ignore into journalissuearticles values(avg.);. However, a recommended minimum thickness of 79 – 140 mm was obtained from design curves for flexible pavement. The average allowable bearing capacity of the soil for square and round foundations is 320 KN/m2. The total settlement obtained varies between 23.92 – 29.77 mm for structural pressure of 100 KN/m2. The embankment suitability index of the soil suggests an expanding, but not collapsible construction material. Summarily, the subsoils have very low suitability/workability index, hence poor/fair performance for roadway, foundation, canal sections, and earth fill dams. The empirical models gave correlation coefficient of: MDD/PI vs. CBR insert ignore into journalissuearticles values(0.0046);, LL vs. coefficient of consolidation insert ignore into journalissuearticles values(0.0127);, PI vs. undrained shear strength/effective overburden insert ignore into journalissuearticles values(0.0074);, PI vs. angle of shearing insert ignore into journalissuearticles values(0.0420);, dry density vs. angle of shearing insert ignore into journalissuearticles values(0.4022);, suitability index vs. CBRs insert ignore into journalissuearticles values(0.0968);, clay contents vs. PI insert ignore into journalissuearticles values(0.0777);. Schist and quartzite dominated the area, having high value as foundation constructions, aggregate in pavement, and building stone, hence can be trusted in most engineering construction works.
Keywords : Settlement, Flexible pavement, Geotechnics, Geoinformatics, Bearing pressure

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