Before starting any excavation project or any construction work that involves breaking ground, it is best practice to conduct an underground utility survey.
Before starting any excavation project or any construction work that involves breaking ground, it is best practice to conduct an underground utility survey. Doing so prevents accidents from happening and avoids damages to existing utility services such as gas and water pipes. On that, there are different methods and equipment used in conducting the survey. One of which is a ground penetrating radar. Sydney utility locating firms use ground penetrating radar services due to its many advantages.
What is a Ground Penetrating Radar (GPR)?
A GPR is a non-destructive method that uses radio waves or radar pulses to detect, locate and image subsurface objects.
How Does It Work?
A ground penetrating radar transmits radio waves to the ground at varying frequencies. The frequency used depends on the application but the average for utility locating is 450Mhz. The radio waves are reflected by subsurface utilities and these are detected by a receiver antenna. Then, a computer records the time it took from transmission to receipt. This is how the location and depth of a utility are determined.
When the GPR system or device detects an underground structure, it reflects the energy at a different wavelength depending on the type and material of the structure. This enables the identification of different utilities.
What Are Its Advantages?
Ground penetrating radar services are used in utility mapping because they can locate both metal and nonmetal objects without any physical connection. Some of the subsurface objects it can detect are:
Post tension cables
Stormwater drainage pipes
Additionally, it can detect void spaces.
Given its nature, a GPR enables locators to detect hidden utilities in inaccessible areas particularly in densely-populated cities like Sydney or Melbourne. It also does not pose any threats to the safety and health of workers and causes no damage to any structure present. Moreover, a utility mapping survey can be completed with less to no downtime using a GPR.
Does It Have Limitations?
Yes. As great as ground penetrating radar services are, it still has its limitations. Utilities cannot be detected if they are buried in a pile of similar structures sharing the same conductivity. However, this is very rare.
Another concern is the response of the type of soil to a ground penetrating radar. Sydney service locating firms like us admit that some soils are transparent to GPR while others like silts and clays are not. These types absorb radiowaves which prevent it from travelling underground. Hence, the necessity of using other methods and equipment in conducting an underground utility survey.
Despite its limitations, ground penetrating radar services are still a recommended utility locating method due to its non-destructive and cost-effective nature. And here at One Search, we provide total service locating solutions from GPR services to concrete scanning to vacuum excavation. If you are new to utility location, our team will walk you through the process and help you determine the best solutions based on your needs.