Browsing by Author "Iheme, K. O."
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Item Geotechnical Evaluation of Lateritic Soil in Baba-Ode Area, Ilorin, North – Central Nigeria(Published by Department of Civil Engineering, University of Ilorin, Ilorin, Nigeria, 2019) Obaro, R. I.; Odediran, O. A.; Iheme, K. O.; Akakuru, O. C.; Gbadebo, A. F.This study was carried out on lateritic soil at Baba-ode,North-central Nigeria with aim of denoting the geotechnical properties of lateritic soil and its suitability as construction materials. Two disturbed lateritic soil samples (sample A and B) were selected for the various laboratory techniques. The grain size analyses, the specific gravity tests, the atterberg limit tests, compaction, California bearing ratio and shear box tests were carried out on the samples. The grain size analysis shows that sample A is gravelly silt – clayey sand while sample B is silt – clayey gravel composition. Atterberg consistency limit test indicate that sample A has 30.0%, liquid limit 19.5% plastic limit, 10.5% plasticity index, 9.1% shrinkage limit while sample B has liquid limit of 27.0%, 16.2% plastic limit, 10.8% plasticity index and 7.4% shrinkage limit. The soil samples are above the activity (A) line in the zone of intermediate plasticity (CL) which suggests that they are inorganic soils. The samples contain inactive clay indicating little or no swelling tendency and therefore good for construction materials and this would prevent foundation failures. The California Bearing Ratio (CBR) values are 2 – 3% (mean = 2.75%) and 2 - 4% (mean = 2.75%) in sample A and sample B respectively. This implies they are good as subgrade construction materials. The compaction tests for the optimum water content for sample A is 15.0% and 13.0% for standard and modified proctor respectively. The standard and modified proctor for sample B is 15.2% and 14.0% respectively. The compaction tests for Sample A indicate a higher fine fraction and thus a higher optimum moisture content while sample B has higher coarse fraction with lower optimum moisture content. The cohesion falls within 70-90Kpa (mean = 80Kpa) and the internal friction ranges from 250 - 310 with mean of 290. The results obtained from geotechnical analysis suggest that the soil have high bearing capacity, hence, it can be used as construction materials in engineering works. The soil could also support shallow foundation, dam construction, embankments, slope stability and subgrade materials in road constructions.Item PRELIMINARY ASSESSMENT OF LIQUEFACTION AND LANDSLIDE POTENTIALS IN SOILS FROM THREE MAJOR SUSCEPTIBLE AREAS IN NIGERIA(Published by Faculty of Physical Sciences, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria., 2018) Ige, O. O.; Oyeleke, T. A.; Iheme, K. O.Landslide is one of the most ravaging natural disasters in the world and recent occurrences in Nigeria require urgent technical assessment of susceptible zones. In this study, three major susceptible areas in Nigeria were accessed for potentials for liquefaction and sliding. The areas are Oko (Anambra State), Agbaja (Kogi State), Enyenkorin and Asa Dam (Kwara State). Reconstructed samples were collected from each locality for the purpose of determining and comparing their susceptibilities to landslide and liquefaction. Grain size analyses and Atterberg consistency limits were used to investigate the liquefaction potential while the slope conditions were deduced using SLOPE/W software. Grain size distribution revealed that the soils contain 0-7% gravel, 63- 96% sand and 2-18% fines for Oko and Agbaja compared to 4-12% gravel, 30-36% sand and 18-39% fines for Asa Dam and Enyenkorin. These values and plots of plasticity index against liquid limit, dry density against moisture content and coefficient of permeability show that samples from Oko and Agbaja are potentially liquefiable when compared with the control sample. The shear strength parameters have values ranging 40-80 kPa and 24-35o while the Coefficient of permeability varies between 1.71 × 10-5 and 1.18 × 10-3. The factor of safety (FOS) values for soils from Oko, Agbaja and Asa Dam are 1.452, 1.946 and 2.488 respectively. Though these values indicate stability, caution must be applied as the condition at the area revealed that the slope are in their state of impending failure. The FOS for dry slope was higher when compared to those of wet slope. This was due to the effect of pore water pressure on the soil as it reduced the shear strength of the soil. A reduced value of FOS was observed in the model under loading conditions, which indicates loading as a contributing factor to the slope failure. It is recommended that proper and efficient drainage system should be employed in these areas to reduce the influence of pore water pressure in the soils. Also surface terracing is recommended to reduce the effect of toe failure.