Ramboll maps ground conditions with marine acoustics for Statens Vegvesen as part of placement study for Fv862 new crossing Tromsø-Kvaløya, in northern Norway.
Almost 90 km of profile is collected and interpreted and 9 different survey areas are investigated.
Statens Vegvesen (the Norwegian Road Administration), are planning a new connection across Sandnessundet between Tromsø and Kvaløya. The connection is planned to help reducing traffic queues along Fv862 in Tromsø municipality.
In relation to these plans Statens Vegvesen performs an initial placement study to ensure that the most optimal type and area for a connection is chosen. Costs, traffic densities, nature values, population and geology are just some of the important tasks in relation to building of a new connection. Statens Vegvesen has to know as much as possible before they choose a crossing solution. Statens Vegvesen has chosen 9 different survey areas for initial investigations.
The geology is one of the most important factors to be aware about when type and place for large constructions are chosen. Bad knowledge of the geology can delay or stop a project totally and can of course be very expensive. Ramboll has Scandinavia’s largest engineering geophysical department and has done many kind of site investigation surveys for the transport and energy sectors, also for Statens Vegvesen.
Statens Vegvesen asked for acoustic measurements, which is one of our specialities. Ramboll has recommended single channel seismic with a sparker system from Geo Marine services, which we find to be one of the best choices in these geological conditions.
This type of survey is very good in the initial phase, because a large area can be mapped in a very short time. The results give indications of internal structures in the sediments and depth to bedrock, which is the geological information required in this phase of the project.
At a later stage there will be need for more detailed information on the mechanical properties of the materials. Which methods are used for that investigation is determined by the type and place of the final crossing solution. Often the detailed investigation includes a refraction seismic survey to map the mechanical properties of soil and rock, and to locate weakness zones in the rock. We perform this type of investigation on a regular basis for Statens Vegvesen and other clients in Norway.