Back calculation of the Sørkjosen’s landslide.

• Main Author: Kalogeropoulou Marianna
• Other Authors: Nordal Steinar
• Format: Master Thesis
• Language: unknown
• Published: NTNU 2020
• Subjects: Detour; Norway; Skotheim; Sørkjosen; Finnmark; Troms
• Online Access: https://hdl.handle.net/11250/2779347

Norway is exposed to frequent landslide activity. A large number of landslides occur each year, causing damage to infrastructure, or even loss of lives. Due to the changing climate and the extreme weather patterns, the landslide activity in Norway is expected to increase. A shoreline landslide with a volume up to 1,4 million m3 took place at Sørkjosen, a village in Troms and Finnmark county, at the night from the 9th to the 10th of May 2015. The shoreline slid into the sea over more than 1 km and parts of the local harbor were destroyed. No persons were killed but after the landslide the traffic had to take a 700km detour through Finland to pass the site. The slide occurred in a fjord with steep slopes and a large river delta. Also, there were ongoing road construction prior to the event, including rock blasting. Some of the destabilizing factors are presented below: • Filling and roadworks • Low tide • Precipitation (24,9 mm) • Excess pore pressure (10kpa) The main objective of this report is to gain a greater understanding for this event. Undrained analysis is carried out in the finite element method program ‘Plaxis 2D’. In the investigation that took place in 2016 (Nordal.S, L’Heureux.J, Skotheim. A, 2016) NGI-ADP material model was used for the stability calculations. In this report the Mohr- Coulomb material model has been used for various simulations with constant and varying undrained shear strength of the clay layer. The simulations must be regarded as containing significant simplifications on the real slide event, as they do not account for three- dimensional effects.