- Scott Allen
Ground Penetrating Radars 101
Updated: Dec 5, 2022
What are Ground Penetrating Radars?
Ground-penetrating radar (GPR) technology has become the technology of choice for industries that need to know about what lies in the ground.The technology is safe to use and noninvasive, it’s ideal for studies involving landscaped areas, indoor spaces, and public locations. GPR is a geophysical method that uses radar pulses to photograph the subsurface. The GPR unit sends pulses of waves in the microwave band, with frequencies typically ranging between 1 and 1000 MHz. The strength of this which is also known as amplitude, depends on the conductivities between the materials the signal passes through, and how the impulse reacts is primarily determined by the object’s density and size.
GPR applications range from Geotechnical Investigations, Utility Detections, Environmental Investigations, Structural Analysis, the list goes on.
AllRock is a Ground Penetrating Radar scanning company in Toronto, Ottawa and Newfoundland and Labrador.
What are the benefits of using a GPR?
Prevents problems: Construction sites may have inherited problems on the site such as erosion-prone areas or loose soil. By noticing these areas before construction begins by using a GPR, you can avoid potential problems by planning to accurately prevent them.
It works almost anywhere: GPR’s are so advance that it can penetrate through most materials easily. This allows for a more accurate detailed result that will give a understandable demonstration of exactly what the site looks like below the surface. No noise: There is no noise with a GPR. If you were to excavate the area, it would create noise and pollution.
Do not need to excavate:
Before GPR’s were discovered, engineers had two choices to check out the establishment of the ground: they could excavate the ground, or they could use schematics. With schematics, possibly may not include all items to be found, which could cause complications over the years.
How do GPR’s work?
1. The radar unit transmits a pulse of electromagnetic energy into the ground through an antenna transmitter (TX).
2. The electromagnetic energy reflected back from any target(s), layer(s) or object(s) detected is recorded by the receiving antenna (RX).
3. The received signal contains information regarding position and depth relative to the transmit point. The time delay between sending and receiving signals is dependent on subsurface conditions which affect the velocity dispersion of the electromagnetic energy wave.
4. Data converted from audio to visual signals form for display for user.
What do GPR’s Detect?
GPR’s can be used for a wide variety of findings. This subsurface tool is the most effective when there is a large difference between electromagnetic property of target(s) and materials surrounding the area. GPR’s are often used to map items made of the following materials:
Ø Natural Materials (soil, rocks, etc)
GPR’s are frequently used to detect:
o Air pockets or voids
o Geological features and rock obstructions
o Changes in ground Strata
o Underground Utility Pipes and lines
GPR scanning in Toronto at a busy intersection will likely uncover very different features than a project in Northern Ontario. It is helpful to understand where you are working and get a background of utilities and geologies prior to beginning work on the project.
Utility Mapping Applications:
Subsurface utility mapping takes choice of GPR technology to increase the accuracy of their work when combined with traditional locating methods. GPR’s provide assistance in locating unmarked utilities, subsurface mapping, structures, and excavating projects.
Advantages of GPR’s:
o Less expensive than other methods
o No digging, excavating, or ground disturbance will be demanded
o Data is provided quickly and is able to cover a large amount of area
o Data collected during the survey can be viewed immediately or used in foreseeable projects
o Frequencies can be regulated to deliver a range of resolution and penetration depths
o It makes it possible to measure the dimensions, thickness, and depth of target(s)
AllRock offers Ground Penetrating Radar (GPR) scanning in Ottawa, Toronto and Newfoundland and Labrador.