Ground Penetrating Radar (GPR) is a nondestructive method of scanning the subsurface. It can be used to detect a range of objects including geologic formations, contaminant plumes, grave sites and utilities. GPR units transmit high-frequency radio waves that penetrate the soil. Reflections from underground objects that differ from the surrounding soils are received by an antenna and recorded by the unit’s controller. To detect most underground utilities, frequencies in the 200MHz to 600MHz are common.
Who Uses GPR?
GPR is used in numerous fields. Engineering applications include nondestructive testing to locate buried structures and utilities. It is also used to locate remediation sites for environmental purposes and to assess geologic features. Military personnel sometimes use Ground Penetrating Radar to detect mines, unexploded ordnances and tunnels.
What Can You Find with GPR?
In utility applications, GPR is primarily used to locate lines made of plastic, terra cotta and other non-conductive materials.
What is the Benefit of GPR?
GPR is an important supplemental method of remotely sensing certain underground facilities and structures. Under some conditions, it may be used to detect underground utilities made of non-conductive materials which electromagnetic pipe and cable locators cannot detect.
Is GPR Right for My Project?
The successful use of GPR to sense the presence of underground utilities or other anomalies is highly dependent on favorable conditions including depth of bury and soil composition. GPR is most effective where soil makeup is homogeneous like dry sand. Most of coastal Florida, for example, is favorable for GPR applications. GPR will also detect many non-utility objects such as tree roots, rocks, rubble or anything else that differs from the surrounding soils. This tends to make GPR data analysis highly subjective and time consuming when compared to pipe and cable locators.
GPR is just one of many tools in the A/I/DATA toolbox. A/I/DATA will advise the use of GPR when it is an appropriate method for a utility investigation task.