Papers by Olaoluwa Akintorinwa
akamaiuniversity.us
Geophysical investigation was carried out along segments of the Ilesa-Akure highway located in th... more Geophysical investigation was carried out along segments of the Ilesa-Akure highway located in the Precambrian Basement Complex of Southwestern Nigeria with a view to establishing the cause(s) of the road pavement failure. Four failed segments and two stable segments serving as control were studied. The magnetic and the Very Low Frequency Electromagnetic (VLF-EM) measurements were taken at intervals of 5 m along traverses established parallel to road pavement. The Vertical Electrical Sounding (VES) involving the Schlumberger array and 2-D imaging using the dipole-dipole configuration were adopted for the resistivity survey. The magnetic and VLF-EM results revealed that the control stable segments are founded on a near homogeneous substratum devoid of major geological features while anomalies typical of linear features suspected to be fault/fractured zones and lithological boundaries were identified within the failed localities. The geoelectric sections generally identified four geologic layers comprising the topsoil, weathered layer, partly weathered/fractured basement and fresh bedrock. The subsoils on which the road pavement was founded at control stable segments have moderate to high resistivity values (>200 Ω-m) while the subsoils on which the failed segments are founded are of relatively low resistivity values that are generally less than 200 Ω-m. Network of suspected linear (geological) structures such as fractures and faults were identified from the 2-D resistivity structure across the failed segments. The causes of highway pavement failure in the studied highway may have been clayey topsoil/sub-grade soils with characteristically low resistivity values of < 200 Ω-m and near-surface linear features such as faults, fractures and lithologcal contacts beneath the highway pavements.
International Journal of Physical Sciences
Geotechnical tests were carried out on twenty subsoil samples obtained from ten locations at the ... more Geotechnical tests were carried out on twenty subsoil samples obtained from ten locations at the depth of 1 and 2 m within Federal University of Technology, Akure, Nigeria. The area is typical of basement complex. The test include; Natural Moisture Content, Grain Size Analyses, Specific Gravity, Atterberg Limits, Compaction, California Bearing Ratio (CBR), and Unconfined Compression Tests. The ten locations where the soil samples were collected were selected across the geological classification of the area. ArcGIS 10.1 software was used to generate maps showing the geotechnical parameters distribution across four geological formations within the area at 1 and 2 m depth. It was observed that the distribution of each geotechnical parameter correlates with the composition of the weathering endproduct of the geology. The rocks underlain the area includes; Migimatite Gneiss, Quartzite, Charnockite and Biotite Granite. The poorest geotechnical parameters were obtained within subsoil underlain by Charnockite, hence are most unsuitable soil to host the foundation of civil engineering structures, while the area underlie by weathering end-product of quartzite rock is of good geotechnical parameters and most suitable soil to host the foundation of civil engineering structures. The weathering end-products of Charnockite, Migimatite and Granite rocks give relatively high shear strength than that of quartzite, indicating low cohesive nature of the weathering end-product of quartzite.
The velocity-deviation log, generated by combining the sonic log with the neutron-porosity log, p... more The velocity-deviation log, generated by combining the sonic log with the neutron-porosity log, provides a tool for characterizing the predominant pore types and fractures in clastic drilled holes in the Niger delta area. Five geophysical wireline logs comprising lithology and porosity logs were acquired for the study. The velocity-deviation is calculated by converting neutron porosity-log data at a reasonable (VTA) depth interval to a synthetic velocity using time-average equation while the sonic porosity-log data (Vsonic) is converted to a sonic velocity by taking the reciprocal of the interval transit time ('t) at the same (Vsonic) depth intervals of interest. The difference between the sonic velocity and the neutron log-derived (VTA) synthetic velocity is utilized in generating the velocity-deviation log. The resulting velocity-deviation, which could be 'negative' 'zero' or 'positive' log is the result of the variability of velocity at equal porosity....
Journal of environment and earth science, 2014
Hydrochemical analysis was carried out on surface and groundwater samples collected from Akure me... more Hydrochemical analysis was carried out on surface and groundwater samples collected from Akure metropolis with a view to determining their quality. Hydrochemical data on groundwater samples from fifty six (56) boreholes were sourced from the Ondo State Water Corporation. Twenty five (25) surface water samples from streams and rivers in the study area were collected and analyzed using standard analytical techniques. The analyzed physical parameters include colour, odour, turbidity, conductivity and chemical properties such as pH, dissolved solid, hardness, cations, anions and heavy metals. All the groundwater samples were colourless, odourless and tasteless. Some surface water samples were coloured and turbid in appearance while some had objectionable odour. Although the NO 3 - concentration levels in both surface and groundwater samples were generally below the WHO threshold value of 10 mgl -1 , relatively high concentration range (2.5-6.0 mgl -1 ) was recorded within the city centr...
NRIAG Journal of Astronomy and Geophysics, 2018
Geophysical investigations were carried out along two failed segments of Akure-Ijare road, named ... more Geophysical investigations were carried out along two failed segments of Akure-Ijare road, named locality 1 and locality 2, with the aim of establishing the cause(s) of the incessant pavement failure along the road. The geophysical investigations involved the Very Low Frequency Electromagnetic (VLF-EM) and Electrical Resistivity Methods. The VLF-EM measurements were taken at intervals of 10 m along traverses parallel to road pavements. Two techniques were adopted for the electrical resistivity method namely: the vertical electrical sounding (VES) and a combination of horizontal profiling and sounding using dipole-dipole configuration with inter stations separation (a) of 5 m and an expansion factor (n) that varies from 1 to 5. The Schlumberger configuration was used for the VES with AB/2 varying from 1 to 65 m. Nine (9) and twelve (12) VES were carried out at localities 1 and 2 respectively. The VLF-EM method revealed that the road pavement is founded on a weakly conductive material...
Journal of Geography and Geology, 2015
Erosion index map of Akure Metropolis was developed using an integrated remotely sensed, geologic... more Erosion index map of Akure Metropolis was developed using an integrated remotely sensed, geological and soil data. This was with a view to classifying the metropolis into different erosion risk zones. Administrative and topographic maps, geologic and soil maps, Landsat ETM+, Aster DEM and thirty two (32) erosion types data were acquired. Landsat ETM+ was pre-processed for geometric correction, haze reduction and re-sampling. Optimum index factor and covariance analysis were carried out in order to determine the least correlated bands and these bands were subjected to convolution filters, texture analysis at 3X3 window size, histogram equalization, de-correlation stretch, principal component analysis (PCA) and the Aster DEM to topographic analysis such as sink fill and shielded relief to generate slope map and lineament map. All the derived maps including the soil map were reclassified and given risk values according to their order of degree of contribution to either accelerate or decelerate soil erosion. Using weighted index overlay raster tool in ArcGIS software, all thematic maps were captured in GIS environment to produce a composite erosion index map of the study area. Existing erosion type data were used to establish the reliability of the erosion index map. The erosion index map classified the Akure Metropolis into three zones-very low risk (57.5%); low risk (33.9%) and moderate risk (8.6%). Most parts (91.4%) of the metropolis fell within the very low to low risk zones with tendency for sheet/reel erosional features. Areas with moderate risk with tendency for gully erosion were located on the high slope region.
Global Journal of Pure and …, 2006
Velocity-Porosity relationship in some parts of Niger Delta was studiesd with a view to establish... more Velocity-Porosity relationship in some parts of Niger Delta was studiesd with a view to establish the velocity-porosity relationship and the generalized equation(s) that best describe this relationship in clastic formations. Five wireline logs were acquired for the study. Neutron porosity log ...
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Papers by Olaoluwa Akintorinwa