Is GPR suitable for my site?
GPR is widely used for a host of applications within the engineering and construction industry, archaeology and forensic sectors, in geological and environmental science, and for utility detection and concrete inspection. GPR is an ideally safe technique for evaluating concrete, and has the highest resolution of any subsurface imaging, non-invasive method. GPR collection is rapid, undertaken at walking pace, and offers complete coverage of an area whether it be a wall, road, field, car park, basement, brownfield or greenfield site.
The GPR systems we deploy are highly portable and comprise a handheld control unit connected by cable to the antenna, which operates at a range of frequencies that vary according to the target type and depth of penetration required. At higher frequencies, smaller targets, as well as closely spaced targets, are more readily detected than when using alternative detection techniques.
Below is a table of antennas we use to meet many requirements within a broad range of applications (depths may vary dependent on ground conditions):
|Frequency||Typical depth of penetration (bgl)||Common applications|
|2600 MHz||to 0.4m (12in)||Concrete evaluation|
|1500 MHz||to 0.7m (20in)||Concrete evaluation; void detection|
|900 MHz||0–1m (0–3ft)||Concrete evaluation; void detection|
|400 MHz||0–3m (0–9ft)||Utility, engineering & environmental, void detection|
|200 MHz||0–6m (0–20ft)||Utility, geological, engineering and environmental|
|100 MHz||0–12m (0–40ft)||Geological, engineering and mining|
|50 MHz||0–25m (0–75ft)||Geological|
Large areas up to 1Ha can be covered in a single day using portable karts. In urban areas with many buried obstructions and services, the scan line spacing is reduced in order to provide a more detailed study.
Limitations to the technique include clay rich ground (the signal attenuates more readily so the scan depth is restricted), concrete with very dense reinforcement (multiple layers with bars less than 100mm apart) and significantly vegetated or uneven ground (the antenna requires a good coupling to the ground in order to transmit quality signals).
Mini examples of range of deployment
50MHz MALA rough terrain antenna - coupled with GPS allows the deepest penetration in the most difficult of environments. Depth to bedrock and straitigraphic mapping are common apps.
120MHz shielded GSSI antenna deployed to locate the presence of deep manmade structures such as culverts at 5-10m depth.
400MHz antenna mounted on a kart system across a road to locate the presence of buried pipes and utilities within 2m depth.
New 2GHz palm antenna offers the ability to accurately map man made structures. It is able to reach tightly spaced areas such as corners of walls and roofs.
Still unsure? Please contact or call us on on 01442 416656 and we'll be happy to help further.