Authors :
Ezenta N. K; Nwachukwu M. A; Umunnakwe J. C
Volume/Issue :
Volume 8 - 2023, Issue 1 - January
Google Scholar :
https://bit.ly/3IIfn9N
Scribd :
https://bit.ly/3Ims0Jx
DOI :
https://doi.org/10.5281/zenodo.7662832
Abstract :
This investigation is motivated by the concern
over the siting and stability of engineering structures
and anthropogenic activities situated within the
watershed area of the Otamiri River in the Imo River
basin in Nigeria. Using electrical resistivity inversion and
soil sampling, this study research is anticipated to look
into the differences between the soil properties and
water table in upstream and downstream watershed
areas of the Otamiri river. This will lead to different
approaches in engineering practices land use planning,
watershed management, and better management of
water resources within the study area. In order to create
a topographic map of the area, GPS was utilised to
measure spot elevation and coordinates. Four VES
stations were set up to map the subsurface tomography
using the electrical resistivity inversion technique. Two
composite soil samples that were taken from the VES
stations at a depth of 5 metres were examined in a lab.
Geotechnical properties measured include shear strength
and bearing capacity, liquid and plastic limits, grain size
distribution and compaction density. Through the
geophysical modelled data we obtained three types of
curves, A curve type for VES 1 & 4, QH curve type for
VES 2, and UK for VES 3. Common lithology discovered
within the study area is sandy-clay, siltstone, sand and
gravel. The topsoil from VES 1, 2, 3, and 4 ranged from
1.3-ohm meter to 1223.4-ohm meter. The water table
ranged from 19.57m to 54.39m. The geotechnical results
revealed a plasticity index of 13.3% to 19.3%, optimum
moisture content at 14.0% to 14.4%, and maximum dry
density of 1.85mg/m3 to 1.86mg/m3. The trial test
showed shear strength at 99.5KN/m2 to 109.8KN/m2
indicating high shear strength and a great tendency to
withstand the load. Most measured parameters fell
within recommended standard of the federal ministry of
Works and housing.
This investigation is motivated by the concern
over the siting and stability of engineering structures
and anthropogenic activities situated within the
watershed area of the Otamiri River in the Imo River
basin in Nigeria. Using electrical resistivity inversion and
soil sampling, this study research is anticipated to look
into the differences between the soil properties and
water table in upstream and downstream watershed
areas of the Otamiri river. This will lead to different
approaches in engineering practices land use planning,
watershed management, and better management of
water resources within the study area. In order to create
a topographic map of the area, GPS was utilised to
measure spot elevation and coordinates. Four VES
stations were set up to map the subsurface tomography
using the electrical resistivity inversion technique. Two
composite soil samples that were taken from the VES
stations at a depth of 5 metres were examined in a lab.
Geotechnical properties measured include shear strength
and bearing capacity, liquid and plastic limits, grain size
distribution and compaction density. Through the
geophysical modelled data we obtained three types of
curves, A curve type for VES 1 & 4, QH curve type for
VES 2, and UK for VES 3. Common lithology discovered
within the study area is sandy-clay, siltstone, sand and
gravel. The topsoil from VES 1, 2, 3, and 4 ranged from
1.3-ohm meter to 1223.4-ohm meter. The water table
ranged from 19.57m to 54.39m. The geotechnical results
revealed a plasticity index of 13.3% to 19.3%, optimum
moisture content at 14.0% to 14.4%, and maximum dry
density of 1.85mg/m3 to 1.86mg/m3. The trial test
showed shear strength at 99.5KN/m2 to 109.8KN/m2
indicating high shear strength and a great tendency to
withstand the load. Most measured parameters fell
within recommended standard of the federal ministry of
Works and housing.