Keller Geoteknikk has introduced the Wet Soil Mixing method for the first time in Norway/Trondheim with support of Prof. Michal Topolnicki, Soil Mixing Expert from Keller Poland. The Client (Veidekke) and the consultant/designer (NGI) came up with two different Soil Mixing options to Keller for the foundation of a 16-story apartment. After the soil condition and design specification were assessed by Keller, together with the designer and the client, Wet Soil Mixing was chosen as a solution to the foundation system. Design was performed by NGI with input from Keller regarding expected strength criteria. 194 pcs of columns with a diameter of 1,2 meter and length of 18,5 meter were designed as floating columns. Upon completion of the columns, pre-loading was planned to be applied prior to commencement of construction works of the apartment.
Prior to the production of the columns, trial columns were constructed in the end of May 2023. In total, 31 trial columns were installed with different production parameters and binder dosages to determine the best combination to obtain high quality mixing and design strength value. Since there haven’t been any previous experience of the wet soil mixing technique with Norwegian clay, trial columns were very crucial for the entire project. Based on several discussions regarding the results of the trial columns with the client and consultant/designer, Keller started production of the project columns in middle of June 2023. 50% of the total project has been completed as of end of June and production continues successfully with an expected completion within July.
For the quality control and design check, wet grab sampling and core drillings are done. Unconfined compression tests have been performed in both Keller’s own testing container and Norwegian University of Science and Technology (NTNU) laboratories. Keller also supported NGI to install fiber-optic cables in five project columns which will be used to measure strains during both pre-loading stage and in the service life of the building. Data obtained from this project will be a valuable engineering source to assess the performance of the first constructed wet soil mixing application in Norway.
Keller is looking forward to collaboration with Veidekke and NGI for future projects. Thanks to all parties involved in this project for the openness to bring expertise from Europe to Norway for the best technical and economical outcome for the project.
