Dam safety assessment using 2D electrical resistivity geophysical survey and geological mapping
A combination of Geological mapping and two-dimensional electrical resistivity (2D-ER) surveys was applied to study the Unilorin Dam and its environment. The purpose of the study was to investigate the dam for structural anomalies that may compromise the purpose and safety of the dam. Field equipmen...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2020-01-01
|
| Series: | Journal of King Saud University: Science |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1018364719318038 |
| _version_ | 1818067376233512960 |
|---|---|
| author | W.O. Raji A.D. Adedoyin |
| author_facet | W.O. Raji A.D. Adedoyin |
| author_sort | W.O. Raji |
| collection | DOAJ |
| description | A combination of Geological mapping and two-dimensional electrical resistivity (2D-ER) surveys was applied to study the Unilorin Dam and its environment. The purpose of the study was to investigate the dam for structural anomalies that may compromise the purpose and safety of the dam. Field equipment for the study comprised a SuperSting R8/IP Multi-Electrodes Resistivity Meter, 84 metallic electrodes and the accessories, compass clinometer, and portable GPS equipment. Geological data were processed and plotted to obtain a Geological Map and Rosette Diagram that were used for structural interpretations. The structures interpreted include an asymmetric fold and a strike-slip fault. The 2D resistivity data were processed and tomographically inverted to obtain the resistivity models of the subsurface around the dam. Interpretations of 2D resistivity models showed that the dam reservoir floor is underlain by competent basement rocks, however, the basement rock is weathered in some places. Patches of low resistivities structures interpreted as seepages, fractures and water-saturated cavity were delineated in different sections of the dam. The surface structural elements from geological study support the subsurface structures interpreted in the 2D resistivity models. Weathered structures, fractures, and seepage in the reservoir floor constitute areas of excessive water loss in the dam. The cavity delineated in the dam foundation is a potential threat to the dam’s safety. The dam section with cavity has been referred to structural engineers for detailed study. Keywords: Two-dimensional electrical resistivity survey, Geological and structural mapping, Tomographic inversion, Dam, Basement complex rocks |
| first_indexed | 2024-12-10T15:22:42Z |
| format | Article |
| id | doaj.art-978fbad10fe74e079d072c380d8fa6ba |
| institution | Directory Open Access Journal |
| issn | 1018-3647 |
| language | English |
| last_indexed | 2024-12-10T15:22:42Z |
| publishDate | 2020-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of King Saud University: Science |
| spelling | doaj.art-978fbad10fe74e079d072c380d8fa6ba2022-12-22T01:43:39ZengElsevierJournal of King Saud University: Science1018-36472020-01-0132111231129Dam safety assessment using 2D electrical resistivity geophysical survey and geological mappingW.O. Raji0A.D. Adedoyin1Department of Applied Geophysics, University of Ilorin, PMB 1515, Ilorin, Kwara State, Nigeria; Department of Geology and Mineral Sciences, University of Ilorin, PMB 1515, Ilorin, Kwara State, Nigeria; Corresponding author at: Department of Geophysics, Unievrsity of Ilorin, PMB 1515, Ilorin, Nigeria.Department of Geology and Mineral Sciences, University of Ilorin, PMB 1515, Ilorin, Kwara State, NigeriaA combination of Geological mapping and two-dimensional electrical resistivity (2D-ER) surveys was applied to study the Unilorin Dam and its environment. The purpose of the study was to investigate the dam for structural anomalies that may compromise the purpose and safety of the dam. Field equipment for the study comprised a SuperSting R8/IP Multi-Electrodes Resistivity Meter, 84 metallic electrodes and the accessories, compass clinometer, and portable GPS equipment. Geological data were processed and plotted to obtain a Geological Map and Rosette Diagram that were used for structural interpretations. The structures interpreted include an asymmetric fold and a strike-slip fault. The 2D resistivity data were processed and tomographically inverted to obtain the resistivity models of the subsurface around the dam. Interpretations of 2D resistivity models showed that the dam reservoir floor is underlain by competent basement rocks, however, the basement rock is weathered in some places. Patches of low resistivities structures interpreted as seepages, fractures and water-saturated cavity were delineated in different sections of the dam. The surface structural elements from geological study support the subsurface structures interpreted in the 2D resistivity models. Weathered structures, fractures, and seepage in the reservoir floor constitute areas of excessive water loss in the dam. The cavity delineated in the dam foundation is a potential threat to the dam’s safety. The dam section with cavity has been referred to structural engineers for detailed study. Keywords: Two-dimensional electrical resistivity survey, Geological and structural mapping, Tomographic inversion, Dam, Basement complex rockshttp://www.sciencedirect.com/science/article/pii/S1018364719318038 |
| spellingShingle | W.O. Raji A.D. Adedoyin Dam safety assessment using 2D electrical resistivity geophysical survey and geological mapping Journal of King Saud University: Science |
| title | Dam safety assessment using 2D electrical resistivity geophysical survey and geological mapping |
| title_full | Dam safety assessment using 2D electrical resistivity geophysical survey and geological mapping |
| title_fullStr | Dam safety assessment using 2D electrical resistivity geophysical survey and geological mapping |
| title_full_unstemmed | Dam safety assessment using 2D electrical resistivity geophysical survey and geological mapping |
| title_short | Dam safety assessment using 2D electrical resistivity geophysical survey and geological mapping |
| title_sort | dam safety assessment using 2d electrical resistivity geophysical survey and geological mapping |
| url | http://www.sciencedirect.com/science/article/pii/S1018364719318038 |
| work_keys_str_mv | AT woraji damsafetyassessmentusing2delectricalresistivitygeophysicalsurveyandgeologicalmapping AT adadedoyin damsafetyassessmentusing2delectricalresistivitygeophysicalsurveyandgeologicalmapping |