3. EM/GPR Imaging Technologies
TEM Methods for Mapping Pipeline Utilities
James P. Cull and Duncan Massie
School of Geosciences, Monash University, Australia.
Abstract
Many urban pipeline systems fail through corrosion in aggressive soils causing considerable environmental damage and economic loss; consequently new geophysical methods are required to investigate the electrical response of the substrate in order to identify areas of potential risk. GPR and galavanic surveys are used extensively for applications of this type but they are costly and inefficient. However equivalent near-surface results can now be obtained using new high-definition TEM systems. In particular the terraTEM and similar systems offer an enhanced turn-off transmitter and multiple samples at early time (500 khz). The enhanced bandwidth provides some overlap with GPR operations and allows greater depths of penetration. Consequently any significant trends in resistivity and soil corrosivity can be readily established using a small-loop configuration for rapid transit surveys.
Last modified: Thu May 11 10:58:29 2006