Optimisation of electrode arrays used in 2D resistivity imaging surveys

2007 ◽  
Vol 2007 (1) ◽  
pp. 1-4 ◽  
Author(s):  
M. H. Loke ◽  
Fouzan A. Alfouzan ◽  
M. N. M. Nawawi
Keyword(s):  
Electrode Arrays ◽  
Resistivity Imaging ◽  
2D Resistivity Imaging ◽  
2D Resistivity

scholarly journals Geophysical Assessment of Subsurface Conditions at Proposed Building Sites: Implications for Foundation Failure and Building Collapse

2018 ◽  
Vol 64 (3) ◽  
pp. 8-20
Author(s):  
Stephen Oluwafemi Ariyo ◽  
Julius Ogunmola Fatoba ◽  
Olateju O. Bayewu ◽  
Kamaldeen Olakunle Omosanya ◽  
Muhedeen Ajibola Lawal
Keyword(s):  
Geological Mapping ◽  
Geophysical Investigation ◽  
Building Collapse ◽  
Resistivity Imaging ◽  
Geotechnical Investigations ◽  
Weathered Layer ◽  
Electrical Sounding ◽  
2D Resistivity Imaging ◽  
2D Resistivity ◽  
Wenner Array

Abstract Building collapse has been a recurrent environmental hazard in Nigeria in the last two decades. This is a corollary of inadequate foundation investigation prior to construction, poor government policies, and general lack of awareness on the importance of geophysical and geotechnical investigations. In this study, geological mapping and detailed geophysical investigation using Electrical Resistivity Imaging (ERI) and Vertical Electrical Sounding (VES) were carried out to understand the suitability of proposed building sites at the main campus of the Olabisi Onabanjo University (OOU), Ago-Iwoye, Nigeria for construction. Both Wenner array and dipole-dipole were used for profiling and Schlumberger for sounding. Four transverses and VES were used in each of the three areas investigated. Our results show that the subsurface of the study areas is underlain by Precambrian basement rock of Nigeria. Rocks in the study area include banded gneiss, porphyroblastic gneiss, biotite-hornblende granite and quartzite schist. The sounding stations across the three areas and 2D resistivity imaging revealed three principal geoelectric layers, the topsoil, the weathered layer and the fractured/fresh basement with varied resistivity values for each layers. At the VES stations, the three geoelectric layers have resistivity values of 62 to 1182 Ωm, 3.2 to 1360Ωm and 87 to 4680 Ωm. On the 2D resistivity imaging profiles, the resistivity of the three layers varies from 2 to 1182 Ωm, 30to 1360 Ωm, and 40 to 2904 Ωm for the topsoil, the weathered basement, and fractured/fresh bedrock. Our work demonstrates that some of the proposed sites are structurally incompetent for engineering or foundation purposes. Excavation of the topsoil and reinforcement are required to sustain the proposed structures.

GROUND INVESTIGATION USING 2D RESISTIVITY IMAGING FOR ROAD CONSTRUCTION

2016 ◽  
Vol 78 (7-3) ◽  
Author(s):  
Haryati Awang ◽  
Rini Asnida Abdullah ◽  
Sabira Abdul Samad
Keyword(s):  
Road Construction ◽  
Imaging Method ◽  
Borehole Data ◽  
Resistivity Imaging ◽  
Resistivity Profile ◽  
Ground Investigation ◽  
Crushed Aggregate ◽  
2D Resistivity Imaging ◽  
High Topography ◽  
2D Resistivity

This paper présents finding on the ground exploration using 2D resistivity imaging. The study was conducted to verify the borehole result, which shows a conflict between the actual site conditions. The proposed study is to investigate of high topography area for road construction. Electrical resistivity imaging method was used for estimating bedrock at Bandar Sri Sendayan, Negeri Sembilan. The site consist of acid intrusive igneous, which is dominantly covered by granite. Two lines of resistivity survey were conducted to identify ground material of this area. The survey was conducted using ABEM Terrameter equipment, where a two-dimensional resistivity profile has been identified for ground exploration and subsurface profiling. The resistivity images showed the existence of boulders and bedrock in multiple weathering grades with resistivity values ranges from 50 to 10 000 ohm-m along the proposed road alignment. The presence of these boulders and weathered bedrock probably not suitable to be used as domestic supply for road material such as crushed aggregate especially at depth less than 30m from surface. Soil or overburden was discovered 12m from the surface. The finding shows the mismatched between the borehole result and resistivity profile, where the borehole data was interpreted as bedrock however the resistivity result proved that it is a boulder.

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