Temporary
casings |
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Hui
Hon began piling works at the Yuen Chau Kok site in February
1998 using a vibrator that did not have sufficient force
to drive the temporary casings down to the founding level
required by the contract. On top of this, Hui Hon
were coming up against a number of soil problems.
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Temporary
casings were driven down, supposedly to the designated
bedrock level |
Two months later, in an attempt to speed up the work,
Hui Hon replaced the vibrator with a Bauer BG 40 drill
rig, a machine with greater capacity. However, because
suitable parts were lacking, this machine could not be
used at full power. Nor was Hui Hon mastering the inherent
geological problems. The progress of works was falling
further and further behind schedule.
The problem was aggravated by the fact that not enough
temporary casings were available to permit the construction
of several piles at the same time.
So, in a totally misguided and unscrupulous attempt to
deal with these issues, the directors of Hui Hon decided
not to install the temporary casings right down to the
proposed founding level. Where the shaft walls lacked
temporary casing support, they collapsed and the shaft
caved in.
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