Risk assessment - NGI
Risk assessment - NGI
Risk assessment - NGI
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Terminologi brukt i<br />
risikohåndtering<br />
Presentert av<br />
Unni K. Eidsvig
Terminologi<br />
Vår inkonsistente bruk av begreper og<br />
definisjoner og manglende enighet om ett<br />
sett av definisjoner vanskeliggjør<br />
kommunikasjon innen fagfeltet<br />
risikovurdering/risikohåndtering.
Definering av termer brukt i<br />
risikovurdering<br />
• Glossary of <strong>Risk</strong> Assessment Term. ICG (=<br />
International Centre for Geohazards) rapport,<br />
International Society of Soil Mechanics and<br />
Geotechnical Engineering (ISSMGE)<br />
Andre:<br />
• Australian Geomechanics Society (AGS)<br />
2000:Landslide risk management concepts and<br />
guidelines<br />
• Canadian Standards association (CSA) 1997: <strong>Risk</strong><br />
management, guideline for decision-makers<br />
• International Union of Geological Sciences’ Committee<br />
on <strong>Risk</strong> Assessment (IUGS) 1997: Quantitative risk<br />
<strong>assessment</strong> for slopes and landslides- The state of the<br />
art<br />
• Land Management Handbook No 56.
Håndtering av fare og risiko<br />
Risikohåndtering<br />
(<strong>Risk</strong> management)<br />
Risikovurdering<br />
(<strong>Risk</strong> <strong>assessment</strong>)<br />
Risikoanalyse<br />
(<strong>Risk</strong> analysis)<br />
Iterativ<br />
og<br />
integrert<br />
prosess<br />
Fare analyse<br />
(Hazard analysis)<br />
Historiske data<br />
(Inventory)
Kjernebegreper i seminarets<br />
program<br />
Begrep<br />
Fare (kvalitativ) / trussel (danger)<br />
Fare (kvantitativ) – Hazard<br />
Typisk benevning<br />
Pr. år<br />
Sårbarhet – Vulnerability Ubenevnt, mellom 0<br />
og 1<br />
Konsekvens – Consequence<br />
Risiko - <strong>Risk</strong><br />
Verdi: kroner / tapte<br />
liv<br />
Tapte liv pr. år,<br />
kroner pr. år
Begreper brukt i farevurdering<br />
Deterministisk<br />
CONVENTIONAL ANALYSIS<br />
Input parameters<br />
ΣF x = 0 → Load effects<br />
Factor of safety =<br />
Load(s)<br />
(Resistance/Load effs)<br />
Resistance<br />
strength, unit weight, ……<br />
Shear strength<br />
ANALYSIS ACCOUNTING FOR UNCERTAINTIES<br />
ΣF x = 0 → Load effects<br />
Input parameters<br />
G x = Resistance – Load effs<br />
Load(s)<br />
P f = P[G x < 0]<br />
Resistance<br />
(P f = P [Load > Resistance])<br />
strength, unit weight, ……<br />
Model uncertainty<br />
Output of analysis<br />
Factor of safety<br />
Factor of safety<br />
Output of analysis<br />
Probability of failure<br />
Reliability index<br />
Parameter(s) which cause failure<br />
Probabilistisk<br />
Density function<br />
2,0<br />
1,0<br />
0,0<br />
0 1 2 3 4<br />
Shear strength<br />
Density function<br />
1,0<br />
0,5<br />
0,0<br />
-1 0 1 2 3 4<br />
Margin of safety<br />
F X = equilibrium equation<br />
G X = limit state function<br />
P f = probability of failure
Begreper brukt i farevurdering<br />
• Frekvens (frequency)<br />
• Pålitelighet (reliability)
Begreper brukt i<br />
konsekvensanalyse<br />
• Risiko utsatte<br />
elementer (elements<br />
at risk)<br />
• f , N par (f, N pairs)<br />
• F-N kurver (F-N curves)<br />
• Tap (loss)<br />
f, Annual probability of occurrence (<br />
1.E+0<br />
1.E-1<br />
1.E-2<br />
1.E-3<br />
1.E-4<br />
1.E-5<br />
1.E-6<br />
1.E-7<br />
1 10 100 1000 10000<br />
Canada<br />
China<br />
Colombia<br />
Hong Kong<br />
Italy<br />
Japan<br />
Nepal<br />
Norway<br />
N, Number of fatalities
Eksempel på risiko typer<br />
• Individuell<br />
• Samfunnsmessig<br />
• Akseptabel (acceptable)<br />
• Tolererbar (tolerable)
Akseptable verdier for individuell<br />
risiko – forslag fra artikler<br />
Slopes<br />
Individual risk<br />
(loss of life/yr)<br />
Reference<br />
Natural slopes 10 -3 Fell & Hartford (1997)<br />
Existing<br />
engineered<br />
slopes<br />
New engineered<br />
slopes<br />
10 -4 – 10 -6<br />
10 -5 – 10 -6<br />
AGS (2000)<br />
New 10 -5<br />
ERM-Hong Kong (1998)<br />
Existing 10 -4
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