Geophysical tools and techniques can and should be used to locate and map man-made underground utilities, pipes, foundations, vaults and other buried structures, prior to drilling or trenching, to avoid hitting and disrupting services.
For locating, marking and mapping underground utilities, a combination of specialized electromagnetic (EM) utility locators, conductivity meters and Ground Penetrating Radar are used. Exact locations are market on the ground surface, using surveyor’s paint or chalk and then accurately surveyed and mapped to document lines that were found.
Non-metallic or non-conductive pipes and culverts can be located and mapped using a transmitter sonde inserted into the line, and with GPR under favorable soil conditions.
Large buried structures like vaults, sumps, or disposal pits, can also be located, typically using a combination of magetic, EM and GPR techniques.
GPR can also be used on concrete structures to determine variations in concreate thickness, to detect voids and to accurately map embedded rebar and wire mesh
