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Program Technical Symposium / General Assembly 2018 in Norway

Date: 20/21. June 2018

Location: Symposium and GA in the conference center Meet Ullevaal Stadion (Oslo) / Excursion to

Kongsberg and Rjukan

Language: (Euro-)English

Technical Symposium – Wednesday 20. June 2018, Brann box – MEET Ullevaal Stadion (Oslo) 8:30 Registration and welcome coffee

9:00 Welcome address Luuk Dorren (BFH)

9:10 Introduction to the technical symposium Karl Kleemayr (BFW)

Session I - “Landslide and rockfall hazard analysis” 9:15 Keynote: State of the art on prediction and modeling of landslides Fausto Guzzetti (IRPI-CNR) 10:00 Shallow landslides and a changing climate in the western United States Kevin Schmidt (USGS)

10:20 Topographic model for rockfall travel distance revisited: a new method

for predicting energy line angle values (results of the Alpine Space

Interreg project RockTheAlps)

Frédéric Berger (IRSTEA)

Session II - “Geohazards in Norway and Sweden” 10:40 Landslide risk management in Sweden Yvonne Andersson-Sköld

(VTI)

11:00 Next generation hazard mapping Heidi Hefre (NGI)

11:20 Introduction to geohazard problems in the Telemark region Kalle Kronholm (SKRED AS)

11:40 Historical landslides in Rjukan – introduction to the field excursion Ulrik Domaas (NGI)

Lunch (12:00 – 13:30) 13:30 Regional early warning system for landslides in Norway Graziella Devoli (NVE)

Session III - “Shallow landslide disposition modelling” 13:50 SlideforMap – a tool for regional landslide disposition modelling Luuk Dorren (BFH)

14:05 SOSlope – the new physically-based spring-block model for shallow

landslide disposition

Denis Cohen (COSCI)

14:20 Implementation of species specific root reinforcement in SOSlope Massimiliano Schwarz (BFH)

14:35 Coffee break

General Assembly (GA) – all members invited 15:00 Start of the GA (the detailed program will be sent to the participants)

16:00 End of the GA

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Excursion Departure for the excursion – Wednesday 20. June 2018, Ullevaal Stadion (Oslo) 16:15 Bus departure 18:30 Arrival in the Storaas hotel, Jondalsveien 1530, 3614 Kongsberg

19:30 Evening dinner in the Storaas hotel

Excursion in the Telemark region – Thursday 21. June 2018 8:15 Bus departure from the Storaas Hotel

9:15 Arrival in Rjukan

9:20 Short introduction to the history of Rjukan

9:45 The 1927 landslide and NGI Projects in Rjukan

11:45 Cable car (Krossobanen) up to the Gvepseborg Panorama Café

12:00 Lunch in the Gvepseborg Panorama Café + free time to enjoy the view

14:00 Bus departure to Drammen

16:15 Slope stability problems in quick clays (Drammen)

17:15 Bus departure from Drammen to Oslo

18:00 Arrival in Oslo

Fifth ecorisQ General Assembly

Norway, 2018Excursion: Rjukan, Tinn municipality, Telemark CountyThe 1927 landslide event and some NGI-projects.

NGI: Heidi Hefre & Ulrik Domaas

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Norge i 3D med Norkart Virtual Globewww.norgei3d.no/

Gaustatoppen

Krossobanen3

Geology – NGU: http://geo.ngu.no/kart/arealis4

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Susceptibility maps

Flooding Debris flow Rockfall

NVE: https://atlas.nve.no

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Skriugata

Såheim Church

Tveitolia

Moe Vestre

Vemork

Mæl

Jordskred Mæl, Tinn 1983

1983.05.10 debris flow hit one house/other houses evacuatedCause: heavy rain + snowmeltNew dirt road/undersized culvert – water lead along the roadUncontrolled drainage on two sitesRelease area: 30cm soil on top of moraineRunout area by house: 4m high debrisExcavator on site/no one responsible/house destroyed7-10. may 60 mm (last day 32mm)Warm weather the last 4 days before event

Rjukan: 821mm/year1983 event: 4%

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Moe Vestre 20041366/20110742Kinder garden – hazard warning P>1/1000 Debris flow deflecting dam Operated by the municipality

Ravine

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Housing area secured with deflecting damCinder garten secured with hazard warning

(prognosis forecast:50mm/day=closed)Debris slides in 1927 + in spring 2004: hit housing area.7 debris slides in this area in 1927Housing areas on debris cones

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Tveitolia.Measurements of rock movements

since 1975 – 1995

Rock fall Debris slideHazard zone hazard zone

Catching dam/gabion

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Acute situation at Tveitolia 2015

2015.09.02 – acute situation: debris slide/-flow hazard

20 houses evacuated (Tveitolia)

85 mm precipitation last 24 h

Cathing dam did not drain water properly

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The 1927 landslide/debris flow eventWeather report 1927:

1 day 2 days 3 days 5 days 10 daysTuddal 121.0 156.1 177.9 200.0 223.1Rjukan 134.0 148.3 178.6 201.4 213.4

Observed precipitation 21.06-30.06 1927

Tuddal 1896-1993Rjukan 1884-

1 day 2 days 3 days 5 days 10 days

mm år mm år mm år mm år mm år

Tuddal 121.0 300 156.1 300 177.9 230 200.0 230 223.1 90

Rjukan 134.0 700 148.3 200 178.6 230 201.4 230 213.4 65

Probable repeat interval for similar precipitation intencity as in 1927

Dato 28.06.1927 28.06.1927 28.-29.06.1927Time interval 08-14 14-19 19-08mm 19.2 40.5 74.3mm/hour 3.2 8.1 5.7

Precipitation and intencity in Rjukan 28-29.06.1927

* Return interval: 700 year

* High intensity the last 12-15 hours

* Saturated ground prior to the last

dayAnnual pres. 1960-1990: 834mmLast day 16% of annual pres.

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Debris slide by the church 192715

Hospital/church

Rockfall hazard zone 1/1000 Debris flow hazard zone 1/1000With unsertainty zone

Historic Rock slide east of HospitalCatching dam above hospital

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Såheim, Rjukan 192717

313-building

now new store

Hazard zone debris flow

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Skriugt.

Ref. Einung: The immense snow masses in the mountains; snow cover until June due to a cold winter, also down the mountain sides. A sudden warm weather changed the situation in a few hours.

The debris slides in Skriugata in 1927 was released in the slopes 60-70m above the houses and not in the mountainside above.The terrain behind the houses was changed by human activity when the houses in Skriugata was built in 1914. The excavation of building sites took out the foot of the slope. It was also made a small road above that led the water away from the normal drainage path.

These human made changes increased the debris slide hazard and is part of the explanation of the incidents in Skriugata in 1927.

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Vemork, Rjukan, municipality of Tinn.

Lidar scan = efficient method – volume and stability

Transport of heavy equipment. Upgrading the Vemork Power plant, Rjukan, 2010.

Optech ILRIS-3D laser skannerDifferential GPS. LiDAR data: 28 000 m3

fracturesurface

LooserockPrelease

ConsequensesRisk

Methods

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Historic events: Vemork railway/road

1927-2010:

30 rockfalls on the «Vemorkbanen» railway, now road

4 debris slides

Historic events (Hydro Energy, Newspaper)

Expect 2 events per year

1927

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Geohazards in Norway: Quick clay slides

•Last 100 years mainly releasedby human activity

•River and stream erosion is important

•Rare, large events withpotentially large consequences.

•150 fatalities last 150 years

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Recent quick clay slides, with large consequences!

Skjeggestad (2015)Lyngseidet (2010)

Sørum (2016)

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Rissa, Trøndelag, 1978

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From left: - Schematic picture of clay sedimented in fresh water (a) and in salt water (b), (after Pusch, 1970. Fra SGI -"Kvicklera – bildning och egenskaper – litteraturstudie". Karin Rankka, 2003) / A picture series of quick clay: loading, remoulded clay, adding table salt, and firm clay after mixing the salt into the clay pore water.

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Risk evaluations of quick clay slides in Norway29

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NORWEGIAN GEOTECHNICAL INSTITUTENGI.NO

#onsafeground

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