Electrical Resistivity Method Research Articles

Effects of thermo-oxidative aging on progressive bending damages and electromechanical behaviors of carbon fiber/epoxy 3D woven composites

The effect of thermo-oxidative aging on mechanical properties is important to designing carbon fiber-reinforced composites serviced in long-term atmospheric environments. Here, we report the progressive bending damage behaviors of carbon fiber/epoxy 3D angle-interlock woven composites (3DAWCs) after thermo-oxidative aging. Three-point bending tests were conducted to characterize bending damage behaviors after different aging days. The electrical resistance change of 3DAWCs was also simultaneously measured with the two-probe method during three-point bending tests. Combining side image and digital image correlation (DIC) technology, we found that the bending strength and modulus deteriorated rapidly during thermo-oxidative aging. The strain distribution and progressive bending damage modes also changed significantly, i.e., a symmetrical strain distribution for the unaged specimens, while the existing interface cracks of the aged specimen changed this symmetry. The electrical resistance method (ERM) effectively identified the early-stage damages, and the first derivative of the rate of resistance change (FDC) revealed differences in the progressive damage modes of aged and unaged specimens.

Resistivity and chloride diffusion coefficient of cement-based materials characterized by non-contact electrical resistivity method and resistivity model

The present study involves the application of the non-contact electrical resistivity measurement (NC-ERM) as a non-destructive method to continuously and in-situ measure the resistivity changes of cement-based materials. The NC-ERM was enhanced and utilized to evaluate the resistivity of the materials, and the steady-state chloride diffusion coefficients of various types of cement-based materials were experimentally determined. The results revealed that the highest resistivity was observed in mortar with a sand-to-cement ratio of 1.0 and concrete with an aggregate-to-cement ratio of 0.6, and the steady-state chloride diffusion coefficient increased with the concentration of the pore solution. Furthermore, a novel multi-level series-parallel model was developed to predict the resistivity and steady-state chloride diffusion coefficient of cement-based materials, with calculated values differing by 5% or less. The calculated chloride diffusion coefficient closely matched the value obtained from NC-ERM, indicating the satisfactory accuracy of the non-destructive experiment and theoretical calculation model.

Damage Evolution of Ballastless Track Concrete Exposed to Flexural Fatigue Loads: The Application of Ultrasonic Pulse Velocity, Impact-echo and Surface Electrical Resistance Method

Damage Evolution of Ballastless Track Concrete Exposed to Flexural Fatigue Loads: The Application of Ultrasonic Pulse Velocity, Impact-echo and Surface Electrical Resistance Method

Mapping of Aquifer Characteristics and Reservoir Protective Capacity Variation in Obafemi-Owode Local Government Area, Ogun State South-West Nigeria

Variation of Aquifer potential characteristics and its impacts on the groundwater subsurface protection of the aquiferous zone using electrical resistivity method was carried out at Obafemi-Owode Local Government Area, Ogun State South-West Nigeria with the principal purpose of assessing and rating aquifer protective capacity of the overburden units in the area. Twenty seven (27) vertical electrical sounding (VES) were conducted using Schlumberger configuration with the maximum electrode spacing of 100m at each point using Allied OMHEGA Resistivity meter. The data were interpreted using partial curve matching techniques and computer iteration program using WINRESIST. Parameters such as aquifer resistivity, aquifer thickness, overburden thickness, bedrock resistivity, reflection coefficient and longitudinal unit conductance were calculated and used for evaluating the groundwater yields and vulnerability of the aquiferous zone to contaminant seepages. The range of reflection coefficient is found to be between 0.02 and 0.98 while that of the protective capacity is between 0.00135 and 0.510. Groundwater potentials of the area were categorized as being high (overburden thickness 13m and reflection coefficient less than 0.8); medium (overburden thickness 13m and with reflection coefficient 0.8) and low (overburden thickness < 13m and reflection coefficient. Also, the study area shows a very poor, poor, and moderate protective capacity rating. Seven (7) VES stations have very poor protective capacity, eighteen (18) VES stations shows poor protective capacity and only two (2) VES stations shows a moderate protective capacity rating. Since the illustration the longitudinal conductance revealed the impermeability of the confining layers which is generally ˂ 1.0 Siemens; values ˃1.0 Siemens which indicates zones in which the confined aquifer is subject to protection by the overlying formation materials; these revelations in the study area were possible indications that the groundwater quality status may have been impaired which necessitated the urgent need for the groundwater to be randomly...

Groundwater Protection Assessment using Frequency Domain Electromagnetic Method and Direct Current Electrical Resistivity Method in Papalanto South-West Nigeria

The aim of this work is to assess the extent of protection of the subsurface hydrogeological structures. Fieldworks were performed integrated geophysical techniques namely Frequency Domain Electromagnetic Method (FDEM) using Geonics-EM-34 to determine the vertical and lateral variations of subsurface conductivity probing depths of 20m, 40m and 60m, while subsurface profiles were obtained using Direct Current Resistivity (DCRE) with AGI Super-sting Earth Resistivity meter; current electrode spacing (AB) ranging from 1 to maximum of 100m and the potential electrodes (MN) were consequently changed from 0.25m to 5m respectively. 1141.92 mmho/m was recorded as the highest true conductivity value for the Horizontal Dipole in the second layer (Profile EMPAP5) while the highest true conductivity value for the Vertical Dipole in the first layer was 134.31 mmho/m (Profile EMPAP1). Four principal geoelectric layers inferred from the VES data where the Topsoil is partly lateritic and alluvium, Sandy Clay/Clay/Silt, Sand/Clay/Shale, and Limestone/Sandstone. Resistivity values for these layers vary from 9.78 to 1428, 1.46 to 1057, 1.46 to 451, and 15 to 10,000 Ω m with corresponding thickness of 0.5m to1.43m, 1.29m to 13m, 2.8m to 84.4m and infinity, respectively. The higher resistivity values at the surface and extremes of both edges were indication of little or no presence of leachates or contaminant plume accumulation in other area. Also, there was a noticeable general decrease of resistivity values of formation rock with depth in these investigated areas; this is an indication that the plumes must have infiltrated rapidly into the subsurface through the massive presence of weathered rock materials of average lateral distances of 15m to 167m of considerable depth and thickness of about 24.9m. The degree of leachate contamination range from 0.0007264 mho to 0.668 mho with the highest value in VESPAP2 followed by VESPAP13 and VESPAP19 while VESPAP22 exhibited the lowest conductance.

A geophysical assessment for engineering performance of subgrade soils: a case study of the Ago-Iwoye/Ilishan road, South-Western Nigeria

Geophysical application of electrical resistivity method has been employed to differentiate subsurface target of interest from the encompassing strata along the Ago-Iwoye/Ilishan road in South-western Nigeria. However, a geological model which links variation in lithological characteristics of subgrade soils to the engineering performance of the road is yet to be a research subject. This research is a special geotechnical application of geophysics for revealing the subsurface disposition and predicting the stability state of subgrade materials. Field assessment of rock types, and their relationship was followed by electrical resistivity measurement along the road. Schlumberger and dipole – dipole arrays were adopted for fifty-eight (58) Vertical Electrical Sounding (VES) and 2-D resistivity imaging involving Dipole-Dipole profiling technique was adopted in the sedimentary segment. Field data were inverted to 2-D resistivity structures inferentially delineated contour colorations using ‘DIPRO for Windows’ software. Geo-electric layers revealed Sedimentary Basin (SB) between Ilishan and Irolu, between Irolu and Ijesha-Ijebu, Transitional Zone (TR) with abrupt contrast along the plane of an unconformity and crystalline Basement Complex (BC) towards Ago-Iwoye. The 2-D resistivity structures across the different geological terrains revealed with 50Ωm - 3289Ωm at SB,233Ωm - 8028Ωm at TZ and 8Ωm - 3009Ωm at BC. From geotechnical view, subgrade materials underlying the SB and TZ segments can be adjudged competent to sand and clayey sand units with minor occurrences of incompetent clay and sandy clay lenses. The occurrence of subsurface discontinuities at the BC end of TZof the road would adversely affect the pavement stability.

Non-destructive characterization of pore structure and chloride diffusion coefficient of cementitious materials with modified non-contact electrical resistivity method

The intricate pore structure of cement-based materials passively influences chloride ion transport and mechanical properties. Existing non-contact electrical resistivity measurement (NC-ERM) methods lack precision for rigorous studies. the NC-ERM was upgraded in this research, which is suitable for assessing the pore structure and transport characteristics of hardened cementitious substrates. The results obtained from this method closely correspond to those obtained from CEMHYD3D, Mercury intrusion porosimetry (MIP), and other methods. Additionally, the impact of mixture proportions on the resistivity, pore structure parameters, and chloride ion diffusion coefficient of cementitious materials is discussed. With an increase in sand ratio and sand-to-stone ratio, the resistivity exhibits an initial rise followed by a decline. Chloride diffusion of 5 wt% NaCl-saturated specimens is 1.2–1.3 times higher than 3.5 wt% NaCl. This study provides a novel non-destructive, convenient and accurate method for characterising the pore structure and testing the transport properties of cementitious materials.

Electrical Resistivity Behavior of Saline Soil under Low-Temperature Conditions

Freeze-thaw cycling of frozen soils is known to be the cause of various engineering failures of infrastructure in cold regions. Researchers found that electrical resistivity methods outperform traditional ground surveying methods in frozen soils for their greater convenience and cost-effectiveness. However, detailed investigation into the relationship between the electrical resistivity of soil and a variety of soil properties is still needed. In this study, a series of laboratory experiments using the Wenner method were conducted to determine the relationship between soil electrical resistivity and soil geotechnical properties such as initial water content and pore fluid concentration under freeze-thaw conditions. Cylindrical soil samples undergo artificial freeze-thaw cycles to a temperature as low as −70°C, and electrical resistivity and temperature values are recorded simultaneously. Measurement results are summarized for curve fitting, and a statistical model showing relationship between electrical resistivity and temperature during freezing and thawing was given. Above freezing point, the log of electrical resistivity had a linear relationship with temperature. Below freezing point and above −15°C, the log of electrical resistivity had a square root relationship with temperature. Different trends in electrical resistivity change in extremely low-temperature regions (from −15°C to −70°C) are also discussed. In extremely low-temperature regions, the electrical resistivity of frozen soils did not monotonously increase with lower temperature, which may be because of increasing salt concentration in the unfrozen water phase. The findings of this study are expected to bring more insights to frozen soil structure, and assist in geophysical surveying in cold regions and construction methods utilizing ground freezing.

Groundwater potential zones identification using geoelectrical resistivity sounding and GIS in upper Metro sub-catchment, Malang, Indonesia

Recently, Upper Metro Sub-Catchment and its surroundings have witnessed intensive land investments. The lack of surface water and the human activities of this region increase the demand for groundwater. Several water boreholes were installed to meet the large water needs; however, these boreholes no longer cover the high demand for water due to the increase in population, increase in irrigated areas, and wear and tear on pumps. Therefore, in order to better define the catchment area and find new sites that meet the water quality and quantity requirements, a geoelectrical survey using the electrical resistivity method was carried out in the upper Metro sub-catchment potentials. Using the Schlumberger array, a total of 19 vertical electrical soundings were conducted along 2 profiles. The recorded data were interpreted quantitatively and qualitatively through the use of apparent resistivity maps, geoelectrical pseudo-section analysis, and the established geoelectric sections. In this study, we identified sandstone tuff as an aquifer layer at a depth of 20 – 100 meters. So it can be known that there are 3 zones of groundwater potential consisting of poor, medium, and high.

Electrical Resistivity Techniques for Groundwater Studies in North-Western Part of District Hisar, Haryana, India

Abstract Haryana is one of the dominant agrarian states of India but salinity in the groundwater is one of the major concerns in the state. The salinity in groundwater is observed from top itself in the central part of Haryana consisting of Hisar, Jind, Rohtak, and Jhajjar districts. As a result, local inhabitants are facing severe problems with the nonavailability of fresh drinking water. In some places, shallow aquifers are having marginally saline water which is used by the local inhabitants in dry months. Groundwater even in shallow aquifers also becomes saline due to less rainfall and intrusion of saline water from lower layers. In some areas, the thickness of freshwater columns has been reduced significantly due to the excessive withdrawal of fresh water and intrusion from underlying saline groundwater aquifers. It is therefore pertinent to study fresh/saline groundwater interface to solve these problems on scientific basis. The geophysical methods especially electrical resistivity method has proved very useful for the estimation of fresh/ saline groundwater interface. The present paper deals with the findings of electrical resistivity survey conducted in Adampur and Agroha blocks of district Hisar, Haryana, India. Thirty-five Vertical Electrical Soundings (VES) were conducted in these areas for this purpose. The results indicate that the entire study area is occupied with marginally saline to highly saline groundwater. The study shows the presence of a thin layer of marginally saline groundwater almost uniformly distributed in the entire study area.

CBR Mapping Prediction from 2D Resistivity Imaging Using Regression Following Archie’s Formula

Indirect geophysical methods are increasingly associated with direct underground methods in investigating the subsurface to address environmental and geotechnical problems and reduce the cost of underground studies. These methods make it possible to explore large areas with acceptable precision, time, and cost. The present study combines the electrical resistivity method with the California Bearing Ratio for exploring an area located west of the Nouakchott port in Mauritania. The study aims firstly to verify that the thickness of the backfill layer must be less than 2 m throughout the entire study area and secondly to map areas with low California Bearing Ratio values (<80%) indicating substandard backfill compaction using 2D Electrical Resistivity Tomography imaging survey and regression. The measured Electrical Resistivity values exhibit a good nonlinear regression with California Bearing Ratio, following Archie's equation. A map of California Bearing Ratio variation was derived from the Electrical Resistivity values, indicating the distribution and variation of soil strength in the study area. The results revealed that the backfill layer did not meet the standards, with approximately 35% of the total area having a California Bearing Ratio value below 80%. The areas with poor compaction requiring treatment were primarily located in the southern sector, followed by the middle and eastern sectors.

Geoelectrical investigation to delineate potential aquifers in Shahroud, Iran

One of the world's most pressing needs today is access to groundwater. Although hydrological parameters can generally be estimated using underground studies, these methods are time-consuming and expensive. By taking the direct relationship of these parameters with electrical resistivity and measuring it with a cheaper and faster geoelectric method, a qualitative estimate of these parameters will be obtained. The electrical resistivity method is one of the most widely used methods to probe aquifers. The main objective of this paper is to show how, by interpreting and modeling the data of this exploratory method along with other geological information, the hydrogeological modeling of groundwater reservoirs can be done, and then, with an informed vision, the wells can be drilled for exploitation. For this purpose, the electrical resistivity data at 189 points and 9 profiles in the Shahroud region with Schlumberger array, after reviewing and making some modifications, were subjected to one-dimensional inverse modeling. According to the peripheral vision, the electrode distance was considered to be 50 meters and the length of the profiles is different. The longest profile was 1000 meter and related to profile 3. Then, using the results of modeling along with other available information, the hydrogeological models of the area were prepared in the form of iso-resistivity contour map and interpreted in terms of resistivity and thickness of subsurface layer using computer software Geographic Information System (GIS). Similarly, the thickness map of the aquifer unit (s) was also prepared to classify the good and poor zones. Using the prepared models and also considering the direction and piezometric of the groundwater flow inside the aquifer, suitable places were identified and suggested for future exploitation.

Behavioral assessment of intrinsically formed smart concrete using steel fibre and carbon black composite

In recent years, health monitoring consists of the periodic observation and analysis of existing systems to predict and avoid structural breakdown, thereby saving lives and significantly lowering the cost of structural maintenance and repair. Normally, non-destructive testing techniques and sensor technology are used to detect damage in concrete structures are expensive in nature. Self-diagnosing or smart concrete has emerged a new paradigm in concrete research for damage detection. Smart concrete was cast by blending functional fillers such as carbon black, and steel fibers with concrete to improve the performance. Under various load conditions, the mechanical properties of the proposed smart concrete were examined. The electrical resistance of smart concrete was measured using the Four Probe Method and the Arduino UNO software. SEM and XRD were used to investigate the microstructures of intrinsically smart concrete. Thermogravimetric analysis was employed as a Non-Destructive Testing method to observe the hydration process. Furthermore, the obtained data were linked with the electrical resistivity of the smart concrete to assess corrosion damage. The electrical resistivity method is also an economical method and effective method to monitor the rate of corrosion.

Geophysical Subsurface Mapping Using the Electrical Resistivity Technique: A Comprehensive Study of the Petroleum Training Institute Main Campus in Effurun

The electrical resistivity method was used to conduct a detailed examination of subsurface geology and hydrogeological parameters at the Petroleum Training Institute (PTI) Main Campus in Effurun, Nigeria. The research includes field data collecting, sounding curve interpretation, and dipole-dipole data processing. Both qualitative and quantitative methods were employed to gain a complete understanding of the hydrogeophysical features of the research area. The analysis revealed A and AK formations, which include four, five, and six-layer structures, highlighting the subsurface's intricacy. A frequency table was utilised to categorise the distribution of VES curves within the study area into three major groups. This classification was critical for characterising and comprehending the area's hydrogeological and geological complexity. Geo-electric sections were created to illustrate the different underlying layers, such as topsoil, clayey sand, sand, sandstone, and fracture. The study analyzed geoelectric properties and aquifer zones using resistivity isopach maps in 2D and 3D formats. The northeastern part of the study area had higher resistivity values, indicating geological variables affecting rock composition and groundwater supply. The findings are crucial for effective groundwater resource management, environmental assessments, and regional development planning. The geological model, combining data from dipole-dipole, geo-electric, and VES sections, accurately characterized subsurfaces in the PTI Campus area. The study identified six subsurface layers, providing baseline data for future infrastructure development. Recommendations include using advanced geophysical methods and a more detailed assessment of subsurface geology in the Warri region. This study adds to our understanding of the hydrogeological and geological aspects of the PTI Campus area, allowing us to make more informed judgements concerning environmental and infrastructure design. The study offers a comprehensive analysis of subsurface geology and hydrogeological parameters at PTI Main Campus, contributing valuable insights for groundwater management, environmental assessments, and regional development planning.

Fast Initial Model Design for Electrical Resistivity Inversion by Using Broad Learning Framework

The electrical resistivity method is widely used in near-surface mineral exploration. At present, the deterministic algorithm is commonly employed in three-dimensional (3-D) electrical resistivity inversion to obtain subsurface electrical structures. However, the accuracy and efficiency of deterministic inversion rely on the initial model. In practice, obtaining an initial model that approximates the true subsurface electrical structures remains challenging. To address this issue, we introduce a broad learning (BL) network to determine the initial model and utilize the limited memory quasi-Newton (L-BFGS) algorithm to conduct the 3-D electrical resistivity inversion task. The powerful mapping capability of the BL network enables one to find the model that elucidates the actual observed data. The single-layer BL network makes it efficient and easy to realize, leading to much faster network training compared to that using the deep learning network. Both the synthetic and field experiments suggest that the BL framework could effectively obtain the initial model based on observed data. Furthermore, in comparison to using a homogeneous medium as the initial model, the L-BFGS inversion with the BL framework-designed initial model improves the inversion accuracy of subsurface electrical structures and expedites the convergence speed of the iteration. This study provides an effective approach for fast initial model design in a data-driven manner when the prior information is unavailable. The proposed method can be useful in high-precision imaging of near-surface mineral electrical structures.

Effect of Plantation Density on Some Physical and Technological Parameters of Scots Pine (Pinus sylvestris L.)

The issue of optimising the initial stand density (ISD) of tree plantations has high practical importance. The objective of this study was to non-destructively evaluate the influence of the initial stand density of Scots pine (Pinus sylvestris L.) plantations located in the European part of the Russian Federation on wood basic density (BD), moisture content (MC), ultrasound velocity (UV), latewood content, and drilling resistance (DR). The trees at the age of 45 years with initial plantation densities of 500, 1000, 3000, 5000, and 10,000 trees/ha were tested by a 5 cm-long core sample for gravimetric MCGM and BD by PULSAR-2.2 for UV along the height (UVH) and through the tree trunk diameter (UVD) by the IML-RESI PD-400 tool for DR, as well as by GANN HT 85T for MC based on the electrical-resistance method (MCERM). A significant influence of ISD was found on DBH, UVD, MCGM, and MCERM. ISD had no significant impact on BD, UVH, and DR. The wood BD ranged from 356 to 578 kg·m−3 with a mean value of 434 ± 3.3 kg·m−3 and was restricted by the soil and environmental factors. DBH and 70% MCERM were good indicators of tree vitality. Linear correlations between DBH and MCERM (R2 = 0.67), DBH and MCGM (R2 = 0.74), DR and BD (R2 = 0.71), and the two-factor model MCGM = f(DBH, BD) with R2 = 0.76 were found.

Tensile damage self-monitoring of carbon fiber/epoxy 3D braided composites with electrical resistance method

Electrical resistance method (ERM) has great potential in self-monitoring structural health for carbon fiber composites due to carbon fiber conductivity. Here we report the correlation between tensile damages and electrical resistance changes of 3D braided composites subjected to monotonic and cyclic tensile loading. Experimental and finite element methods were utilized to reveal the electrical resistance variation and damage evolution under monotonic tensile loading. We found that the electrical resistance changes under monotonic tensile loading could be segmented into three regions, namely, linear growth region, transition region and exponential growth region, corresponding to different damage modes. Synchronous and reversible electrical resistance changes at a low strain level (12% of fracture strain) cyclic loading proved the stability and repeatability of self-monitoring capability. While, the abrupt electrical resistance changes at a high strain level (75% of fracture strain), indicated catastrophic failure of the composites. Such kind of correspondence between tensile damages and electrical resistance change under tensile loading enables ERM to achieve the in-situ structural health monitoring of 3D braided composites without relying on external sensors.

Application of Geophysical Methods for Investigation of Groundwater Potential in Layunrun Village, Ogun State, Southwestern Nigeria

An investigation of the groundwater potential of the area for tube well construction has been conducted in Layunrun village in a typical basement complex of Ogun State using electromagnetic and electrical resistivity techniques in geophysical exploration. Six (6) electromagnetic profiles were used, and twenty-eight (28) Vertical Electrical Soundings (VES) were performed along some of the profiles' potential regions. The typical partial curve matching utilized to create the VES curves was examined, and the results were used to create themed maps of the region. Within the study area, between four and six geoelectric layers were found. These layers are Topsoil, weathered layer (clay), weathered layer, fractured basement, and fresh basement. According to the findings, a bigger percentage of the land has an overburden thickness ranging from 9 to 17 m, with a maximum overburden of about 23 m. It also showed how well fractured the research area is, with thicknesses of the fractures varying from about 12 m to more than 30 m. The study area has a good chance of accumulating groundwater and, consequently, developing groundwater through digging boreholes. The outcomes also suggested that a community with similar geological settings may use the electromagnetic method in addition to the electrical resistivity method to identify places with high groundwater potentials.

Monitoring of simulated clandestine graves of victims using UAVs, GPR, electrical tomography and conductivity over 4-8 years post-burial to aid forensic search investigators in Colombia, South America

In Colombia there are estimated to be over 121,000 missing people and victims of forced disappearances. Forensic investigators therefore need assistance in determining optimal detection techniques for buried victims, to give victims’ families closure and for the wider community to see that justice is being served. Previous research has created 12 controlled simulated clandestine graves of typical Colombian murder victim scenarios at 0.5 m – 1.2 m depths in savannah and rainforest sites in Colombia. The 0–3 years of geophysical monitoring results of were published, with this paper reporting on 4–8 years monitoring of both UAV drone results and geophysical data. The UAV results from the year 8 survey, published for first time from Colombia, showed that the simulated graves could still be located using NDVI and NIR multi-spectral data, but not using optical or other multi-spectral data. The 0–3 years of geophysical data found the simulated clandestine graves could be detected with electrical resistivity and GPR methods, with the 4–8 year surveys evidencing that they could still be detected using bulk ground conductivity surveys, GPR horizontal time slice datasets and 2D ERT profiles. Research implications suggest initial use of UAV remote sensing technology to pinpoint likely search areas, before subsequent ground reconnaissance, geophysical surveys and their interpretation, before intrusive investigation methods are employed for detecting missing and disappeared persons in Colombia.

Geophysical and geotechnical investigations of the site of a collapsed two-storey building in Modomo, Ile-Ife, Southwestern Nigeria

Geophysical and the geotechnical methods were used to study the site of a collapsed two-storey building in orderto determine the sequence and competence of the subsurface layers and determine the cause of the collapse of the building. The geophysical method employed the electrical resistivity method involving one dimensional (1D) Vertical Electrical Sounding (VES) and the two dimensional (2D) imaging techniques. Three VES stations were occupied using Schlumberger electrode configuration. 2D imaging data were acquired along four traverses using dipole-dipole electrode configuration. The geotechnical method involved Cone Penetration Test (CPT). CPT data was acquired at two points with the aid of 2.5 ton Dutch CPT machine. The results showed four subsurface layers based on the 1D VES results and 2D imaging results namely: topsoil, weathered layer, fractured basement rock and fresh basement rock. The topsoil resistivity varied from 116 Ωm to 191 Ωm and has thickness of about 1.5 m. It was classified as moderately competent. The second layer is weathered rock with resistivity varying between 92 Ωm and 327 Ωm and of about 8 m to 13 m thickness. This layer is also moderately competent. The third layer is fractured basement rock. It underlies the weathered rock and have resistivity varying from 391 Ωm to 405 Ωm. Its thickness varied from about 2 m to 20 m. This layer is competent. The fourth layer is the fresh basement rock having resistivity varying from 1365 Ωm to 12348 Ωm and is highly competent. The subsurface materials in the area are competent and can sustain the foundation of the building. Hence, the study concluded that the building collapse did not result from incompetent subsurface materials. Factors other than incompetent subsoil material that is human factors are believed to be responsible. This study has demonstrated the effectiveness of geophysical and geotechnical investigations in determining the competence of subsurface materials at engineering sites.