Geology Reference
In-Depth Information
In rock slope design and construction, the fundamentally important
features of discontinuity orientation, lateral persistence, roughness and
in
ll, can only be surmised from typical ground investigation data.
Ground models and assumptions need to be checked as the rock is
exposed. There are many cases of rock slope failure where sliding occurred
on features that were exposed during construction but were either not
mapped by the site staff or the signi
cance not recognised. This can be a
very dif
cult situation in that evenwhere rock is well exposed, the presence
or otherwise of rock bridges or steps along adversely oriented disconti-
nuities can only be guessed at. Care should be taken to note how easily the
rock is being excavated and how stable or otherwise temporary slopes are,
as such information will be helpful in judging the risk.
6.13.3 Fraud
As a
final note, the engineering geologist should be aware that fraud
does occur in civil engineering, as in other walks of life. Whole bore-
holes in ground investigations have been known to be
fictitious,
let alone individual test runs. Cases are known where core from one
site is placed into core boxes at another site. Tests are sometimes not
carried out as speci
ed or results falsi
ed. Data on foundations are
sometimes made up
for example, depths, materials used and test
results (Hencher
et al
., 2005). Engineering geologists need to be aware
that such practice does occur, albeit rarely, and remain alert in their
supervising duties.
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