Geology Reference
In-Depth Information
Facts to be taken into account
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The failure occurred in May 1982, following about 400mm of rain in a few hours.
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Three failures occurred in the upper level of a cut slope (
Figure B3-5.1).
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A piezometer had been installed through the site of the main failure prior to construction of the road.
Measurements indicated that the main water table was below the failure levels and this was con
rmed
by seepage points in the lower slopes.
-
The failures were in predominantly highly and completely decomposed granite (mostly sand-sized).
Two dolerite dykes in the vicinity of the failure were decomposed to fairly uniform silt-sized material
(Figures B3-5.2
an
d 5.3)
.
landslide.
Piezometer
stand pipe
Dykes
