Ground penetrating radar (GPR) is our go-to technology for a good portion of our underground scanning projects. GPR uses electromagnetic waves to penetrate a surface, without causing damage, to discover where subsurface items are located. It is great for locating buried utilities, such as electrical lines, gas lines, pipes, septic systems, and more, so you can safely dig in an area without disturbing them. It can also be used to scan concrete slabs to locate post tension cables or rebar, or to check for reinforcements in a cinderblock wall.
GPR is great technology, but it is far from perfect. In other words, it has some limitations. As a GPR scanning company, it is important that we understand the limitations of GPR, so we know when to bring in other tools to get the information our clients need.
Here are some of the limitations of GPR technology:
GPR Doesn’t Work as Well in Certain Types of Soil
In ideal conditions, GPR is almost a magical technology. It can show us, in astonishing detail, what is located below the ground’s surface. Unfortunately, not all soil conditions are ideal. In saturated soil or soil with high clay content, the images we receive may not be very clear, or the signal may not be able to penetrate as deeply as it could in dry or loamy soil. In addition, extremely rocky soil or ground that contains crushed concrete or an area that is congested with tree roots, for example, can cause the GPR signal to scatter and give us less-than-ideal results.
GPR Is Not Great for Scanning Extremely Large Areas
In order to work properly, GPR scanning must be done near the surface of the area that is being examined. If you’ve ever seen GPR scanning tools, most of them are about the size of a lawnmower. To get thorough results, it needs to travel over every square foot of the area in question to locate what’s underground. If the area is quite large, this could take a long time and therefore be cost-prohibitive for many clients.
GPR is best for scanning a focused area, such as a certain portion of a property on which you want to put a new building or install a new septic tank. It can also show you exactly where in a slab of concrete it would be safe to drill in order to avoid post tension cables.
Ground Penetrating Radar Can’t Tell Us Exactly What We’re Looking At
GPR is great for telling us that something is there that is different from its surrounding environment (soil, concrete, etc.), but it can’t tell us precisely what it is. We can typically tell if something is metallic or non-metallic, and based on our experience, we can often infer what we’re looking at, but GPR technology alone often can’t tell us with 100% accuracy what is below the surface.
This limitation of GPR technology underscores the importance of having trained technicians on hand, like those at Enhanced Scanning, to interpret the data!
GPR Scanning Used in Conjunction with Other Scanning Tools
While GPR is amazing technology, relying solely on GPR is not the always best approach, which is why the Enhanced Scanning team employs the use of a variety of tools on our scanning projects. We will use technologies such as electromagnetic locating, X-ray, magnetometers, and other non-destructive testing tools to either find what GPR cannot, or to confirm the GPR scanning results.
Contact us at Enhanced Scanning to learn more about our multi-tool approach or to schedule service.