Resistivity imaging as a tool in shallow site investigation - A case study

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Abstract

Resistivity imaging in combination with drill hole information is a powerful tool in geotechnical site investigations. Traditionally the resistivity data is inverted with a 2D smooth inversion algorithm, resulting in a minimum structure model. In the geological interpretation it can be difficult to determine sharp layer boundaries in these models. An additional parameterized inversion of resistivity data, using few layer models can make the geological interpretation of the geophysical models easier and better. The data presented was collected as part of a site investigation for a 2 kin long and about 10 in deep railway trench. The geology in the area is sedimentary with Quaternary deposits overlaying limestone. The main issue at this stage of the project was to understand the hydrogeology in the area. The reason for this is to avoid inflow of water to the trench during and after construction. The main aim of this survey was mapping of the thickness and internal structure of the Quaternary deposits. An extensive dataset with geological and geotechnical data from anger- and core-drilling has been available for the geophysical processing and interpretation. We recommend that the traditional 2D smooth inversion of resistivity data is combined with a parameterized layered inversion. In this case the Laterally Constrained Inversion from Aarhus University was used. The possibility to add discrete prior information in the LCI can limit the problem with ambiguity in geophysical inverse modeling. The final model based on both drilling and resistivity data is much enhanced compared to what is achieved using only one of the datasets alone.

Detaljer

Författare
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Geoteknik

Nyckelord

Originalspråkengelska
Titel på värdpublikationGeotechnical and Geophysical Site Characterization
FörlagMillpress
Sidor607-613
ISBN (tryckt)978-90-5966-009-0
StatusPublished - 2004
PublikationskategoriForskning
Peer review utfördJa
Evenemang2nd International Conference on Site Characterization (ISC-2) - Oporto, Portugal
Varaktighet: 2004 sep 192004 sep 22

Konferens

Konferens2nd International Conference on Site Characterization (ISC-2)
LandPortugal
OrtOporto
Period2004/09/192004/09/22