<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Integrated geophysical methods have been used to investigate the competency of the subsoil. The geophysical surveys conducted involve very low-frequency electromagnetic (VLF-EM) and electrical resistivity (ER) methods (dipole-dipole). ABEM Wadi and Ohmega resistivity meter were used to acquire VLF-EM and ER data, respectively, along two traverses. Station interval of 5 m was used for the VLF-EM survey, while inter-electrode spacing for dipole–dipole was 10 m; the inter-dipole expansion factor (<italic>n</italic>) ranged from 1 to 5. KHFFILT software was used to generate VLF-EM profiles and pseudosection, while DIPRO software was used for ER. Results from the ER method revealed the pattern of resistivity variations within the study area. The low resistivity values (11–25 Ohm-m) observed at the southern part of the study area could be attributed to changes in clay contents and degree of weathering in the subsurface. The results from the VLF-EM investigation revealed the presence of near-surface linear geologic structures of varying lengths, depths and attitudes, which suggest probable conductive zones that are inimical to the foundation of the road subgrade.</p></abstract>

Integrated geophysical methods have been used to investigate the competency of the subsoil. The geophysical surveys conducted involve very low-frequency electromagnetic (VLF-EM) and electrical resistivity (ER) methods (dipole-dipole). ABEM Wadi and Ohmega resistivity meter were used to acquire VLF-EM and ER data, respectively, along two traverses. Station interval of 5 m was used for the VLF-EM survey, while inter-electrode spacing for dipole–dipole was 10 m; the inter-dipole expansion factor (n) ranged from 1 to 5. KHFFILT software was used to generate VLF-EM profiles and pseudosection, while DIPRO software was used for ER. Results from the ER method revealed the pattern of resistivity variations within the study area. The low resistivity values (11–25 Ohm-m) observed at the southern part of the study area could be attributed to changes in clay contents and degree of weathering in the subsurface. The results from the VLF-EM investigation revealed the presence of near-surface linear geologic structures of varying lengths, depths and attitudes, which suggest probable conductive zones that are inimical to the foundation of the road subgrade.

Preliminary geophysical investigation for road construction using integrated methods

Materials and Geoenvironment

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Integrated geophysical methods have been used to investigate the competency of the subsoil. The geophysical surveys conducted involve very low-frequency...

Preliminary geophysical investigation for road construction using integrated methods

Published Online: May 31, 2019

Page range: 199 - 206

Received: Jan 27, 2018

Accepted: Aug 15, 2018

DOI: https://doi.org/10.2478/rmzmag-2018-0017

Keywords
Electrical resistivity, roadway subgrade, subsoil competence, clay material, road failure

© 2018 Joel Olayide Amosun et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Preliminary geophysical investigation for road construction using integrated methods

Published Online: May 31, 2019

Page range: 199 - 206

Received: Jan 27, 2018

Accepted: Aug 15, 2018

DOI: https://doi.org/10.2478/rmzmag-2018-0017

KeywordsElectrical resistivity, roadway subgrade, subsoil competence, clay material, road failure

© 2018 Joel Olayide Amosun et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Electrical resistivity, roadway subgrade, subsoil competence, clay material, road failure