Stability Assessment of Earth Dams in the Migmatite Gneiss Complex of Nigeria using Aeromagnetic Data.
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Minna Journal of Geosciences
Abstract
Sheet 201 and 223 part of Ilorin, southwestern Nigeria was studied. The aim was to evaluate the foundation conditions to assess the stability of the selected earth dams. The data set was interpreted to identify dykes, lineaments and magnetic sources controlling subsurface geology. The extracted lineament structures were employed to examine features controlling the distribution of surface and subsurface hydraulic substances cum stability of dam slope. The length and parallelism of magnetic lineaments in some parts of the area suggested emplacement under tensional stress field along preexisting zones of weaknesses. Magnetic susceptibilities are not uniform in the area and were categorised viz: high, moderate, and low. Magnetic intensity range at Asa, Agba and Apodu dam are 126.56 to -20.90 nT, -215.09 to 111.42 nT, and -644.19 to 285.40 nT. The north western part of the Asa and Agba dam area shows little or no sign of faulting and appears to be more stable structurally than the other part of the study area. Thus, the northwestern part where the two dams are located, is stable structurally. Also, the northeastern part of the study area where the Apodu dam is located shows little or no sign of faulting and appears to be more stable structurally. In conclusion, all the three dams are in less structurally active zones and could only likely to have a functional failure rather than structural because the areas near the dams are structurally stable.