Jesper Bjergsted Pedersen

The Norwegian National Rail Administration (Jernbaneverket) is planning 230 km of railway construction and upgrades adapting for high speed trains to reduce commuting times to and from Norway's capital Oslo. Parts of the project are in areas with little or no prior geotechnical knowledge. To enable an efficient and economic ground investigation program, we conducted a high-resolution airborne electromagnetic mapping (AEM) campaign covering 600 km2 in summer 2015. The investigation area includes various types of geotechnical and geological challenges and the AEM data contribute to the detailed railway alignment design. Primary delivery is depth to bedrock varying from tens of meters glaciomarine clay to few meters moraine or coarse-grained sediments. Detailed analysis of the final AEM resistivity models leads to quick clay appraisal, alum shale detection and indications for major bedrock weakness zones. A tight integration of accurate geophysical models and sparse geotechnical data is a key element in this project.