Geotechnical and groundwater geophysics

Abstract

Because of a change in emphasis from power plant siting to projects principally involving process and facility monitoring and certification of existing structures (dams, pipelines, etc.), geotechnical and groundwater geophysics is in quite a healthy state after some lean years following the demise of nucJear energy construction projects. The orders-of-magnitude jump in the computational capability of geophysicists working in these fields has overshadowed advances in instrumentation (e.g., digital enhancement seismographs), field methods (e.g., cross-boreho!e EM), and interpretive procedures. The advent of powerful, affordable microcomputers has enabled expansion into applications demanding finer resolution and quicker turnaround of results. As aresuit, shallow seismie reflection, seismie and electromagnetic geotomography, and the complementary use of surface and borehole electrical resistivity and seismie data wiJl soon be common if not dominant methods in geotechnical and groundwater investigations.Future trends point to increased emphasis on environmental and economie issues (e.g., toxic wastes or the stability of underground petroleum storage facilities), cross-fertilization with petroleum reservoir engineering (process monitoring and detailed reservoir description), and greater involvement of computers in the planning, data acquisition, and interpretive phases of our projects. As computers take over more of the data collection-processing-interpretation sequence, one of the greatest challenges facing us will be to define the proper role of humans and to use the new technology wisely.

<title>Subsurface radiowave tomography imaging in environmental monitoring applications</title>

“…Imaging can characterize the site geology and monitor fluid flow (15) . The conductivity of injected water (brine) can be varied (modulated) to map flow rates in the deposit.…”

Induced polarization effect in reservoir rocks and its modeling based on generalized effective-medium theory

“…To find the parameters of the GEMTIP model, we should solve equation (25) with respect to m. We use the inversion algorithm based on the regularized conjugate gradient (RCG) method [42]. The RCG method is an iterative solver, which updates the model parameters on each iteration using conjugate gradient method.…”

“…The various electrical phase boundary phenomena are of special interest, because they result in a dispersion of the electrical conductivity in the frequency range from 1 mHz to 10 kHz [22]. Eventually Dobecki and Roming (1985) [25], and Tune and Daggar (1990) [26] were the first who reported an application of the IP method in nonmetalliferous environments.…”

Application of electrical resistivity techniques to detect weak and fracture zones during underground construction

“…It has been applied to various fields such as geotechnical, environmental, groundwater, and underground resource exploration (Titov et al 2005;Lapenna et al 2005;Spitzer and Chouteau 2003;Suzuki and Higashi 2001;Dobecki and Romig 1985). The method has been further used for imaging underground structures and its applications are quite varied, especially with regard to geotechnical engineering and environmental projects.…”