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Mitigation of Landslides
in Hong Kong

Hong Kong Fact Sheet Formerly a British colony
 Returned to China on 1 July 1997

Albert T. Yeung
Department of Civil Engineering
University of Hong Kongyg @E-mail: yeungat@hku.hk
5th September 2012

Japan

Where is Hong Kong?

 Population ~7 million
 Area ~1,100 km2
 Annual rainfall ~2,200~2 200 mm
 80% between May and September
 Highest hourly rainfall of 145.5 mmrecorded on 7 June 2008

Natural Disasters in Hong Kong
 Typhoons
 Flooding Landslides

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Cut Slopes Formed for Building &Infrastructure Developments

Cut Slopes Formed for Building &Infrastructure Developments

Cut Slopes Formed for Building &Infrastructure Developments2

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Slopes near Roads and Buildings

Hong Kong is Highly
Susceptible to Landslide Risk

1972 Sau Mau Ping Landslide- 71 fatalities

1972 Po Shan Rd. Landslide- 67 fatalities

 Steep hilly terrain
 Heavy rainfall Dense development3

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Independent Review Panelon Fill Slopes (1976)
1972 Before landslide
1972 After landslide Professor J.L. Knill Professor P. Lumb Professor S. Mackey
 Professor V.F.B. de Mello Professor N.R. Morgenstern Dr. B.G. Richards

1976 Sau Mau Ping Landslide- 18 fatalities

Geotechnical Engineering Office

Civil Engineering & Development Department
 As a result of several disastrous

landslides in the 70’s, the GEO
was set up in 1977 to regulate
the whole process of Investigation
 Designg
 Construction
 Monitoring, and Maintenance of slopes

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Hong Kong Slope Safety System
 Set up,up developed and maintainedby the GEO since 1977
 Objective

Meet Hong Kong’s Needs forth Highest
theHi h t Standards
St d d off
Slope Safety

Hong Kong Slope Safety System Ensure new slopes meet safetystandards
 Rectify stability of old man-madeslopes Mitigation of natural terrain landsliderisk
 Minimize damage caused bylandslides
 Enhance the appearance ofaesthetics of engineered slopes

Ensure new slopes meet
safety standards
 Improvement of slope safety

standards,
d d administratived i iianddregulatory frameworks, andtechnology
 Checking of new slopes
 Enhancement of land use planningpg

Rectify the Stability of Old
Man-made Slopes Rectify substandard Government

slopes Upgrading slopes though the LPM

program Clear squatters on slopes Promotion of slope maintenance Routine
R tiEngineer
E iInspection
Iti
andd

maintenance of government slopes

 Ensure that owners take responsibility

for slope safety

 Provision of information

5

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Distribution of Registered Slopes
Pre-1977 slopes
already checked

18,000Pre-1977 & highrisk slopes
already upgraded

5,500

11,50022,00057,000 Registered Slopes in Hong Kong

Registered Slopes

Pre-1977 &high risk
slopes to beupgraded

Pre-1977 & lowrisk slopes

Mitigation of Natural
Terrain Landslide Risk
 Detailed study
y of natural

terrain landslides
 Types Mechanism
 Mobility

 Inventory of landslides onnatural terrain

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Minimize Damage Causedby Landslides

Enhance the Appearance andAesthetics of Engineered Slopes

 Public education and publicity
pyon slope stability
 Thunderstorm, rainstorm, floodand landslide warning services
 Landslide Potential (rainstorm)
Index (LPI) Landslide emergency service

大頭茶大羅傘Enhance the Appearance andAesthetics of Engineered Slopes簕欓車輪梅

Best Landscaped Slope Award
2003-2004(赤柱 龍德苑)BeforeAfter7

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Outcome of 35 Years’ Efforts
 Success rate in preventing

major
j landslides
l d lidin
i slopeslchecked as conforming tothe current safety standard
exceeds 99.8%
 Large reduction in fatalities
 Overall landslide risk fromsubstandard man-madeslopes reduced

Conclusions
 Past experience,p, on-goinggg

programs, and future directionsof slope disaster prevention in
Hong Kong have been presented
 Research is being carried out todevelop
p a better understanding
g oflandslides and slope stabilization
measures

Strive to further reduce risk

Looking Forward
 Improvement in design

methodology for slopestabilization measures Better geologic information

Thank you!

 Better understanding of thestabilizing mechanisms of soil nails
 Better material for soil nails
 Non-destructive evaluation of soil
nail performance8