Application of Geophysical Methods to Building Foundation Studies

Abstract

A geophysical survey involving the electrical resistivity method utilizing the Vertical Electrical Sounding (VES) and Electrical Imaging Techniques was conducted around the premises of an area within south-western Nigeria with the aim of studying structural defects which may be responsible for future problems and characterizing the soil conditions of the site. A total of 15 VES stations were occupied using Schlumberger Configuration with AB/2 varying from 1 to 65 m. In the electrical imaging, dipole-dipole array was adopted and the two traverses were occupied in the S-N and E-W directions close to where wall cracks and subsurface problems were manifested. Five main geoelectric sequences were delineated within the study area; these include the topsoil (clay and sandy clay), lateritic clay, weathered bedrock (clay, sandy clay and clayey sand), fractured bedrock and fresh basement. A major discontinuity (fracture zone) was discovered along the S-N direction, while a weak zone was also discovered along E-W direction. The result of this research has shown that the causes of the cracks and distress on the walls within the site may have been influenced by the differential settlement resulting from the incompetent subsoil materials and the fractured bedrock on which the foundation of the building was laid.

Dynamic Soil Properties for Construction Site Investigation Using Geophysical Methods

“…The electrical resistivity approach, for example, can provide information on soil and rock strata under the ground based on their resistance properties. This is supported by the writings of various authors, including (Ibitoye et al, 2013;Ofomola et al, 2018;Oyeyemi et al, 2020;Rena et al, 2020).…”

Assessment of geoelectric properties and localized geology as indicators on cocoa (Theobroma cacao) yield in a part of southwestern Nigeria

“…Geoelectric parameters were obtained by manual inter-pretation of the obtained curves using partial curve matching technique of the appropriate set of two-layers Schlumberger theoretical master curves and the auxiliary curves corresponding to them (Orellana and Mooney, 1966). The values (geoelectric parameters) were imputed into the computer for iteration using Software algorithm, RESIST Version 1.0 (Vander Velpen, 1988) to obtain refined smoothed curves from a combined inverse and forward modelling technique, thus producing an iterative computer graphic display (Ghosh, 1971;Sharma, 1997;Ibitoye et al, 2013). The refined results of the interpreted partially matched curves were obtained and found below error limit with Root Mean Square RMS error of <10 %.…”

Emphasizing the significance of site investigation for infrastructural development of the Greater-Jos Master Plan

“…Amadu et al (2018) employed the electrical resistivity method in rock fracture characterization and termed it as economic, efficient and less time consuming in contrast to other subsurface fracture characterization method such as core drilling. It has been used to determine geological structures (Al-Sayed & El-Qady, 2007), to examine structural weaknesses and to characterize soil conditions that reveal geo-electric sequences characterized by resistivity and thickness (Ibitoye et al, 2013;. It has been applied in different geological environment where a 2-D resistivity survey was used to map the stratigraphy and structures of a shallow subsurface effectively as reported by Nordiana et al (2013).…”