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Section 2: Standards and Practices |
1 Earth Science Systems Ltd, Unit 1 Kimpton Enterprise Park, Claggy Road, Kimpton, Herts SG4 BHP, UK
2 Williams Geophysics, The Plumtrees, Fownhope, Hereford HR1 4PJ, UK
Engineering geophysics can play a useful role in assisting the engineering geologist in mapping subsurface features and in particular the targeting of boreholes for detailed investigation. Frequently the problem of the geophysicist is the selection of the most cost-effective technique prior to commencing geophysical surveys at site. At landfill sites the usual problems are location of the subsurface margins, shape of subsurface margins and determination of fill thickness. The physical properties of the landfill material are usually not known and are difficult to measure in the laboratory. A comprehensive multi-component geophysical survey has been carried out using a wide range of geophysical survey techniques profiled across a concealed landfill margin in Southern England to assess the effectiveness of geophysical techniques in solving the above problems. Interpretation of the results indicates that electrical techniques such as inductive conductivity and galvanic resistivity, are the most cost-effective for providing the required information. The results of the more expensive gravity surveys also provide a very effective means of determining the features of the landfill but the physical properties of the landfill prevent the ground penetrating radar and seismic refraction techniques from providing diagnostic information.
