Environmental Engineering Reference
In-Depth Information
Figure 5.9.
Timber supported trench/pit in Happy Valley Dam, Adelaide, South Australia (courtesy
SMEC and SA Water).
Topsoil
Colluvium
Sandstone
Infill
Infill (GP-GM) in
collapse structure
Siltstone
0123m
Scale
Figure 5.10.
Part of log of trench, Sugarloaf Dam showing infill features resulting from slope movement
(Regan, 1980).
of the subsurface materials at sites where there is little natural outcrop. Careful cleanup
by small backhoe or hand tools is usually required to expose defects, particularly in rocky
materials. Trench exposures are logged in a similar manner to test pits as shown in
Figure
5.8
and Figure 5.10.
Following the slope movements which caused disruption of construction of Tooma
Dam (as described in Chapter 2, Section 2.10.3.2), clear evidence of past slope movements
were exposed as infilled extension features in cut faces of access tracks. It was concluded
