Post on 22-Dec-2015
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ENV-3A1Y: Natural Hazards: 2006 - 7
Landslide Hazards
N.K. Tovey
Н.К.Тови
Landslide on Main Highway at km 365 west of Sao Paulo: August 2002
14,607 days ago today
Exactly 40 years ago next Saturday
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• Lecture 1: Wednesday Week 42
– Introduction
• Landslides as a Hazard and their consequences
• background to why they occur
• Lecture 2: Thursday Week 4 12 – 13 EF 1.01
– Types of Landslide
• Lecture 3: Thursday Week 4 14 - 15
– Landslide Warning systems
• Lecture 4: Wednesday Week 5 09 – 10 EF 1.01
– Landslide and Slope Management
• Field Excursion: Thursday Week 5 12 – 17
• Bring Field Clothing and a packed lunch
ENV-3A1Y: Natural Hazards: 2006 - 7
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• Aims of the course• An introduction to Landslide Hazard Management• Factor of Safety• the causes• Why they occur• Can we predict them• the consequences• The types of landslide • Landslide Warning –• Development of the Hong Kong System and what was learnt• Strategic Planning for the future• Slope management
ENV-3A1Y: Natural Hazards: 2006 - 7
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Landslides as a Hazard• Grossly Under Represented as a
Hazard
• Often treated as a secondary issue
• e.g Rain Storm Disasters of 18th June 1972 in Hong Kong
• 2 major landslides each killing over 60 people
• No one was killed by drowning/flooding
ENV-3A1Y: Natural Hazards: 2006 - 7
Failure of slope above Po Shan Road in June 1972
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Landslides associated with• Heavy Rain (Tropical Cyclones)
– ~ 500+ landslides affected man in Hong Kong 28th May to 2nd June 1982.
– As a result of NKT’s actions Yuen Mo village ceased to exist.
• Earthquakes– Cause liquefaction and rise of pore pressures
• Volcanic Eruptions
ENV-3A1Y: Natural Hazards: 2006 - 7
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ENV-3A1Y: Natural Hazards: 2006 - 7
14607 days ago today at 09:15
N K Tovey a second year PhD student was listening to a lecture by Andrew Schofield.
• Theme of lecture was Landslide Hazards
At 09:15 he turned his attention to a landslide disaster which had occurred a few year earlier in Belgium.
A colliery tip collapsed killing around 20 people in the village.
• At precisely the time he was speaking about the disaster
>>>>>>>>>>>>>>>>>>>>>
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• Aberfan: 21st October 1966
• Tip 7 collapsed, engulfed Pantglas School and parts of the village killing 144 mostly children
ENV-3A1Y: Natural Hazards: 2006 - 7
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• Geotechnics – the discipline needed for detailed analysis
• "the application of the laws of mechanics and hydraulics to the mechanical problems relating to soils and rocks"
• Factor of Safety (Fs):
Forces resisting landslide movement arising from the inherent strength of the soil.
Forces trying to cause failure(i.e. the mobilizing forces).
Fs =
ENV-3A1Y: Natural Hazards: 2006 - 7
Fs > 1 stable But is it?
Fs = 1 just stable Fs < 1 unstable
But is it?