Environmental Engineering Reference
In-Depth Information
Figure 5.7.
Section along Sugarloaf Inlet Tunnel showing seismic refraction profiles and deeply weath-
ered unit (Stapledon, 1988b).
5.5.1.3
Electrical resistivity
The electrical resistivity method measures the resistance of the ground to induced electri-
cal current. Interpretation assumes a horizontally layered model. Whiteley (1983) and
Corwin (1999) provide details of the method.
The method has been used to locate fault zones, zones of deep weathering and cavities
(McCann et al., 1987; Smith and Randazzo, 1987). It can also be used in the exploration
of alluvial deposits where permeable gravel and sand beds can be distinguished from low
permeability clays or rock. This capability has been applied in searches for construction
materials beneath alluvial terraces and for foundation materials at dam sites where signif-
icant alluvial deposits occur.
