Geotechnical Considerations for Foundation Design in Parts of Yenagoa, Bayelsa State, Niger Delta Nigeria (Published)
This research was to determine geotechnical properties of the subsoils in some part of Yenagoa and environs to obtain proper foundation design parameters, six towns in Yenagoa local government area, Bayelsa state was investigated. Six geotechnical boreholes was drilled and laboratory studies of soils samples were obtained from 0-20.25m deep. Subsurface soil profiles were delineated followed by determination of their index and mechanical properties, including Atterberg limits, particle sizes distribution, undrained shear strength, shear box test and consolidation coefficient. The general soil profile consists of (from top to bottom), , upper Silty clay horizon (0.0-5.25m thickness) soft to firm for Yenagoa study areas, Medium silty clay horizon (0.75 to 1.5m thickness) soft to firm Yenagoa study areas, low clayey sand horizon (0.75 to 1.5m thickness) soft Yenagoa study areas, peaty clay (1.0m thickness between 3.0-4.0m) soft Igbogene Yenagoa, upper sand horizon (3.0m thickness) silty sand Etegwe town Yenagoa, lower sand horizon (13.5 to 18.0m) silty sand to fine to medium and medium coarse appear in all the boreholes in Yenagoa. Yenagoa sub-soil show clay of high plasticity, silt of intermediate to high plasticity (CH, MI and MH) according to unified soil classification system from the results it shows that pad foundation is more economical in the study areas. Raft foundation is more economical in the six towns study areas of Yenagoa with Allowable bearing capacity of the upper clay layer ranges from 23-128KN/m2 In view of the significant variations in the stratification and engineering geological index properties of the soil in the six towns in Yenagoa while geotechnical data of one location cannot be used as a basis for design of foundation in a nearby land. Axial load carrying capacity for 305, 306mm, 356, 360mm, 406mm, 600and 610mm diameter for bore pile and tubular driven steel cased piles respectively were calculated for all the studies areas. Where high rise building is required in the various study areas. The study shows that the frequent causes of building collapse in Yenagoa are as a result of inadequate geotechnical investigations of the subsoil, poor quality materials, and poor work supervision.
Determination of Water Quality Index of Shallow Quaternary Aquifer Systems in Ogbia, Bayelsa State, Nigeria (Published)
This study evaluates the groundwater quality status of shallow groundwater in Ogbia, using water quality index (WQI) with a view to ascertain its suitability for domestic and industrial purposes. Groundwater samples were collected from thirty (30) functional boreholes within fifteen (I5) communities of the study area. These water samples were subjected to a comprehensive Physico-Chemical Analysis using standard methods. The water quality index (WQI) of the area was calculated using weighted arithmetic mean and statistical package for social science (SPSS) version I5, software. Seventeen (I7) chemical parameters were considered for the WQI calculation. The results revealed that I0% of the water samples were in the excellent category, 46.6% were in the good water category while 43.3% of the water samples were in the poor water category. The high value of the water quality index (WQI) has been found to be mainly from the higher values of Iron, phosphate, pH and electrical conductivity. Also from the result of the sodium adsorption ratio (SAR), it indicates that, the groundwater is not suitable for irrigation.