Geology Reference
In-Depth Information
2. An ongoing and comprehensive research programme is initiated
for all waste streams into waste conditioning, retrievability and
long-term management and the long-term behaviour of radioac-
tive wastes in the environment.
These recommendations still seem eminently sensible, and if that
advice had been accepted then the investigations at Sella
eld would
have proceeded but with a different focus and programme. Oldroyd
(2002) comments,
in retrospect, the whole Nirex enterprise appears to
have been in too much of a hurry
'
. As a result, rather than an ongoing,
well-planned and managed approach to deal with the radioactive
waste disposal problem, the UK efforts seem to have come to a halt
due to fundamental mismanagement.
'
7.8.4 Landslide near Busan, Korea
The failure of slopes and the subsequent costs of remedial works are
often the result of insuf
cient geological investigation and inadequate
interpretation of ground conditions prior to design. This is compounded
by poor investigations into the causes of failures and systemic problems
associated with poorly de
ned responsibilities for the stability of cut
slopes. This was illustrated by the repeated failure of a large slope in
Korea (Lee & Hencher, 2009). The original ground investigation and
design were de
cient, particularly considering the predictable com-
plexity of the geological conditions. Subsequent investigations were
similarly de
cient. As a consequence, the slope failed six times despite
nine reassessments by various professional engineers and the imple-
mentation of several different remedial schemes over a period of seven
years up to a disastrous failure in 2002. During the history of design,
failure and reassessment, the height of the cut slope increased from
45m to 155m and the cost increased from 3.3 million to 26 million
US dollars.
The investigation, design and management of excavation of this cut
slope can all be strongly criticised. There were many warnings that the
slope was not safe and yet opportunities over a four-year period, to
prevent the
final failure, were not taken. Investigations, instrumenta-
tion, monitoring and design fell far short of international good practice
and failed to meet the then current Korean (rather poorly speci
ed)
guidelines. It appears that all (or nearly all) engineers involved in
investigations and review thought that failure would be restricted to
soil. That being so it was only considered necessary to drill and prove
rock for a metre beneath the soil to establish a ground model for
analysis. There was neither appreciation nor understanding by the
engineers that they were dealing with a weathered rock slope with
structural control of mass shear strength and hydrogeology. The slope
was modelled and analysed as if it comprised layers of cheese, albeit
 
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