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Sättningar hos sulfidjordar.jpg

Subsidence of sulphide soils

Published: 20 April 2011

Long-Term Subsidence is a major problem for road and rail expansion in areas with sulphide soils. Sulphide soils are mainly located along the northern coast. In a research project that runs from 2008 - 2013 studied subsidence of sulphide soils to reach important new knowledge for future infrastructure projects.

Construction of the sulphide and is associated with challenges. Sulphide soil generally have low carrying capacity and are very prone touchdown. The foundations, groundwater and engineering aimed at, environmental and / or cost reasons, as a rule to use sulphide on site instead of the excavation. In Sweden there sulphide soils mainly in a wide swath along the coast of northern Sweden. From Gävle in the south to Haparanda in the north. That is, in areas where the infrastructure is now being expanded.

Today, the industry lacks the tools to predict subsidence including long-term subsidence of sulphide with reasonable reliability. Subsidence caused by a plant / building normally deviate significantly from the a priori expected. For the most part are compositions greater than expected, but sometimes less.

 The objectives of this project is to:

  • Significantly improved the prospects for the industry to the sulphide soils to predict the composition process and the overall conditions for a geostructure during its lifetime.
  • Increased knowledge of setting parameters and creep properties of sulphide soils facilitate the choice of foundation method and / or ground improvement method for railways, roads and other structures.

SGI has been under research project built two test embankments on SGI's new sample box of lights outside Kalix next new railway Haparandabanan. The work has been performed in collaboration with the Transport Administration (Haparandabanan) and Luleå University of Technology. The purpose of constructing test beds is that under carefully controlled conditions, ie with fully instrumented embankments and the foundation soil, for a long time studying subsidence including creeping subsidence sulphide.

The research project funded by the Transport Administration, National Geotechnical Institute, Luleå University of Technology and the Swedish Construction Industry Development Fund.

Postgraduate student: Mattias Andersson
Supervisor: Bo Westerberg