Electrical resistivity surveys are commonly used to detect and characterise near-surface buried objects in commercial developments of brownfield sites. 2D ERT profiles arrays predominate in such surveys due to their relatively rapid deployment, good penetration depths and fast data collection rates. However, there is a need to test the optimum array types in such surveys. A scaled-model was used to simulate a large cleared-building wall foundation in gravel-fill at a test facility, before multiple 2D ERT profiles were acquired using different array configurations. Results were used to generate 2D resistivity models using both least-square smoothness-constraint and robust inversion. 2D profile array comparisons showed that the Wenner and dipole-dipole arrays were the best in detecting the cleared-wall foundation, although dipole-dipole arrays better delineated the top of the wall foundation. This study suggests that both Wenner and dipole-dipole array configurations should be utilised to detect buried wall foundations for 2D resistivity surveys.

Maintenance of existing structures and development or reuse of brownfield sites need to determine buried foundations, in terms of location and dimensions, as accurately as possible. Geophysical methods provide an indirect way to look in the ground and provide information about the subsurface that the traditional methods might be unable to. In particular, the electrical resistivity method has been performed in the context of buried foundation surveys. This review spots the light on the main results obtained from utilizing the electrical resistivity method and the most affecting parameters that can influence the obtained resistivity models, and also, focuses on published case studies to merge their findings to understand the interaction among the method, the foundation and the hosting background for buried foundations surveys. The case studies mentioned in this review show the resistivity method's success and highlight the most important parameters that can control the method’s applicability and data interpretation. The integration of the geophysical-traditional methods has appreciable potential for more accurate findings.

The electrical resistivity method has been successfully used to detect shallow buried foundations, almost, by using 2D electrode arrays. Basic geometry foundations (e.g., buried walls) have been investigated, although, more complicated foundation designs (e.g., stepped footing, pile group with a pile cap) are widely used in the construction industry. Investigation of these complicated foundation types, and engaging 3D surveys, therefore, are required. Multiple 3D electrical resistivity forward modeling was used to simulate different foundations (isolated simple footing, isolated stepped footing, combined simple footings, and pile group with a pile cap). The generated data sets then inverted using a robust inversion algorithm where RES3DINVx64 was used to perform the inversion process for the 3D models. The results from the 3D inverse modeling, suggest the pole-dipole and dipole-dipole arrays for all the investigated foundations.

Microtremor seismic surveys are routinely used to provide shear wave velocities that are converted to soil stiffness site profiles. In this paper, we look to assess the feasibility of using trains as seismic sources to characterize near-surface geology, define the optimum survey parameters to collect train-induced vibrations (i.e., array location and orientation to the railway) and find how the geology affects train-induced vibration characteristics. Three-component train-induced shear wave vibrations were recorded on short (44 m) and long (115 m) linear seismic arrays, both parallel and orthogonal to the nearby railway embankment, using standard seismic refraction recording equipment. The collected data were divided into short/long array size/orientation and seismic components for each survey configuration. 1D shear wave velocity-depth profiles were also generated for all data sets. Results showed thst long linear arrays with vertical components, parallel to the railway embankment, was optimal with the greater depth ranges. The vertical component amplitude of train-induced vibrations was found to be affected by the site geology, increasing with the thickening of Quaternary deposits and having different magnitudes for trains traveling in different directions. Results showed that different apparent shear-wave velocities were obtained from different train groups and different seismic components. The passenger trains (i.e. Virgin Trains Pendolino and British Midland 319 series) generate Rayleigh waves at higher frequencies than the freight trains.