Summary of Methods for Measuring Electrical Properties of Geological Strata to Estimate Electromagnetic Shielding Effectiveness
Abstract
This investigation was performed under Project 4A162731AT41, 'Military Facilities Engineering Technology, Work Unit CO-054, 'Electromagnetic Pulse (EMP) Validation of Design Recommendations for C3I Facilities. Principal electrical properties of interest are the dielectric constant and conductivity (or resistivity). Representative measured results reported in the literature for various rock and soil types are included. The measurement techniques considered are: 1) laboratory methods; 2) in situ measurements at the surface of the Earth; and 3) in situ drill-hole measurement methods. Because many factors influence the electrical constants of the real earth, it is highly desirable, when practical, to perform measurements in situ rather than in the laboratory. Methods based on single drill holes provide localized values for the electrical constants in the vicinity of the hole. Propagation between two holes can be used to deduce bulk characteristics of earth medium electrical constants between the two holes. Since characterizing a broad area of the Earth's surface would require data from a large number of holes, this method can be quite expensive. When it becomes impractical to drill holes, in situ surface measurement methods can be substituted. Keywords: Dielectric properties, Electrical conductivity of soils, Electrical measurement of rock.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1988
- Accession Number
- ADA196742
Entities
People
- Lawrence W. Epp
- Raj Mittra
- Ray G. Mccormack
Organizations
- Construction Engineering Research Laboratory