Now the conclusion earth slide in Sørkjosen ready – NRK

The embankment into the sea is the reason it went a mudslide in Sørkjosen last May. The embankment was laid in November 2014 and should be the foundation of a new cross between old and new E6.

It appears in a report investigating committee has made. A special commission was set down to find the cause of the landslide. Professor of geotechnical engineering at NTNU, Steinar Nordal, has led the work.

The landslide was triggered by heavy rains and melting snow a lot, but the embankment is the underlying cause behind. It came 24.9 millimeters of rain in the course of a day, and most came in within 12 hours that fateful night.

– Before we started construction, it was done stability calculations both in Sørkjosen and by celebrations, where the tunnel goes into the mountains. These are areas where we know that the basic conditions are demanding, says project manager Stein Johansen in NPRA.

– The conclusion of the geotechnical report was that the stability of the celebrations was not good enough, and so it was done action here early in the construction phase. Stability in Sørkjosen, however, was considered sufficient.

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Disappeared in the sea

The big landslides closed E6 last year and led to a breakwater, jetty and pier were shattered and fell out at sea. Three houses and three people were evacuated during the night when the slide went.

The police suspects in days afterwards that the seabed had yielded, and thus had reason on land disappeared into the sea.

NPRA were building a new road through Sørkjosfjellet then slide went, and it was speculated that their construction work was related to slide. This was disproved somewhat later.

There were many present when the report was published.

Photo: Eskil Mehren / NRK

Difficult ground conditions

In the process of rebuilding has NPRA made several landslide measures.

• In The celebrations are about 25,000 cubic meters of quick clay dug out and removed. The new embankment is built right on the mountain, and at Høgda is a stone wall replaced with masonry in concrete
• At the pier in Sørkjosen, where exceeded started, replaced soil and clay masses that raged out of rock. Then apply a new rock-fill, which is reinforced with motfylling at sea.

– We do this because the ground conditions here are bad, and it is far from the ocean floor and down to the bedrock. We are working on re-establishing the original embankment, says project Gudmund Løvli.

– Had we known that the ground conditions were not so, we would probably have gone for tunneled around the area, says regionvegsjef NPRA Region North, Torbjørn Naimak.

Oldies death mystery

In January told Nordlys that geologists decided to include the tragic death slide in Sock Elvik in 1959 in the report on landslides last year . It’s a short distance between Sock Elvik and Sørkjosen, and it was never found the cause of the landslide 56 years ago.

Rastragedien led to the village Sock Elvik virtually was destroyed by a mudslide and nine people perished.