Geotechnical Engineering

The Geotechnical Engineering Office (GEO) was established after landslip
disasters in the 1970s. The control of geotechnical aspects of
construction works and upgrading of sub-standard slopes to reduce
landslip risk, continue to be its main duties in terms of staff deployed.
Geotechnical checks were made on 11 686 design proposals during the
year.

As part of the implementation of the recommendations of the Slope Safety
Review Report endorsed by the Executive Council in February 1995,
increased resources were provided to further accelerate the Landslip
Preventive Measures (LPM) Programme. During 1997, a total of $550
million was spent on the LPM Programme to increase the annual output of
slope upgrading works. LPM works were completed on 110 government
slopes and statutory Dangerous Hillside Orders were recommended for
300 private slopes. Preliminary studies were carried out on 12 000 slopes
and detailed geotechnical investigations were completed on 600 slopes.

In 1997, the abnormally prolonged and intense summer rainfall resulted in
547 landslides. The GEO carried out detailed investigations of the more
serious incidents, including those at the Ten Thousand Buddha Temple
and Kau Wai Keng Village which resulted in two deaths.

During the year, work continued on the 'Systematic Identification and
Registration of Slopes in the Territory' (SIRST) project and 'Systematic
Identification of Maintenance Responsibility of Slopes' (SIMAR) project.
A new computerised Slope Information System is being compiled
containing important information on all sizeable man-made slopes and
retaining walls in the HKSAR.

The GEO strives for continuous improvement. During the year, a mission
statement and a five-year strategic plan to achieve the mission have been
developed. The GEO slope safety hotline has been upgraded to provide a
24-hour service to members of the public seeking information on slope
maintenance and slope safety. The emergency system for providing
professional assistance in landslip incidents has been upgraded through
improvements in communications and transport.

The GEO continued the public education campaign on slope maintenance
and slope safety warnings by, inter alia, wide distribution of promotional
booklets and pamphlets, attending media interviews and public seminars,
mounting displays at popular shopping centres and advertising in MTR
stations. The landslip warning messages have been amplified by frequent
TV broadcasting of announcements of public interest. In April 1997, a
slope maintenance audit section was set up to assist maintenance
departments to improve their performance in discharging their slope
maintenance responsibilities.

The GEO continued to inspect squatter villages to identify dwellings
which are especially vulnerable to landslips during heavy rainfall. Up to
1997, 73 800 squatters had been cleared upon the GEO's
recommendations - 58 000 from urban areas and the others from about
200 of the more vulnerable villages in the mainland New Territories.

In 1997, the Hong Kong Geological Survey published a memoir on the
geology of the north-eastern New Territories, completed a book on the
offshore geology of Hong Kong, and digitised four 1:5 000-scale
geological maps of the Kowloon area. It also began a detailed investigation
of the sub-surface geology of the area around Tung Chung New Town,
assisted with several major landslide investigations, and responded to 297
requests for advice on geological matters.

The GEO carries out engineering geological research. Studies of the
volcanic rocks in the Aberdeen and Chai Wan areas were completed in
1997, together with trials of non-destructive engineering geophysical
techniques for site characterisation. Research into the nature and
occurrence of landslides on natural terrain was also carried out, and an
inventory of such landslides was completed and made available for public
reference.

The GEO's Geotechnical Information Unit (GIU) in the Civil Engineering
Library houses the largest collection of geotechnical data in Hong Kong. It
is open to the public and served more than 30 000 users during 1997.

The GEO manages the Public Works Central Laboratory at Kowloon Bay
and six Public Works Regional Laboratories in various parts of Hong
Kong. These laboratories are accredited under the Hong Kong Laboratory
Accreditation Scheme (HOKLAS) to carry out specific tests on
construction materials and to provide laboratory calibration services.
More than 296 tests were carried out in 1997.

The GEO provides ground investigation services for government projects.
In 1997, major ground investigations were carried out for the proposed
Route 16 from West Kowloon to Sha Tin, Tseung Kwan O Development,
South Cheung Chau disposal area and water supply to Tan Kwai Tsuen
North, Yuen Long. Many ground investigations were completed for the
accelerated LPM Programme.

In 1997, the GEO provided geotechnical advisory services to government
departments on a wide range of projects including road improvement
works, such as the Tsing Yi North Coastal Road project, construction of
embankments on soft clay for the Shenzhen River Regulatory Works,
drainage improvement works in Yuen Long, and site formation and slope
works for various other projects.

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