Ground radar is a non-intrusive, high-resolution imaging technology that uses electromagnetic pulses to map subsurface materials and structure. It can locate buried objects, including metal and non-metallic pipes and utility lines, rebar in concrete, detect voids and more. GPR surveys are a valuable tool for many projects, especially where digging, coring or drilling cannot be done for safety or cost reasons.
The effectiveness of a GPR investigation depends on the frequency of the transmitted electromagnetic pulse and the underlying material. Different frequencies provide a trade-off between resolution and penetration depth; higher frequency antennas offer improved data resolution, but lower frequencies allow deeper subsurface investigations. Consequently, it is essential to understand the underlying geology and soil conditions for each project when choosing an antenna frequency.
Exploring Ground Radar: Applications and Advantages
For example, a GPR survey in sandy soil may produce a large number of reflectors that could indicate a gravesite, as shown in the figure below from a survey conducted by GeoModel, Inc. The graves are clearly reflected due to their unique electromagnetic properties that differ from the surrounding soil.
Similarly, GPR can be used to quickly and accurately locate underground pipes and utilities without digging or disturbing the surface. It is also an efficient method for locating potential obstructions in bridge decks, roadways, and tunnels. It can be used in a variety of other applications, such as mapping dams and the internal structure of concrete and earth dams, detecting rebar in construction, locating cracks and damage in walls, floors, ceilings and slabs and investigating lake bed sediments.