Posted By Tim
Hello,

All, just wondering if anyone has had any experience of using these technologies when dealing with underground service identification.

Regards

Posted By PeteA
I have been invloved with GPR in some detail before, and allthough it certainly has its uses, it also has many limitations.

Its really only ever used for plastic utilities, and will only work in suitable ground conditions

It doesnt like very conductve ground and finds it difficult if not impossible to see through wet clay type ground.

On "made up" ground its poor also, you cant really tell the difference sometimes with pieces of rubble and a utility.

Radar will not identify the type of utility either it will only indicate the presence of a pipe or cable.

You also need to think of the physical size of the unit, generally a lawnmower type size, so often unsuitable on some footpaths, and if you have an area with many different utilities again it becomes difficult.

Often found it to be better on plastic mains running down a carriageway that are recent, this way the radar not only sees the pipe but also the difference with the backfill materials

So to sum up, it does have its uses on plastic pipes, conventional locators are far superior on metallics though and Radar certainly isnt the X ray specs like some people believe it to be.

Posted By mrs.seed
Our contractors regularly use 'air spade' tools. They do seem to be very good in the right ground conditions. Brilliant in sandy/gravel types soils but not much good in heavy clay. I believe this is because they work by forcing air into the soil. With heavy clay there are no gaps/fissures for it to go down, whereas with gravel/sand there is.

We do also use ground radar, but it relies on the interpretation of the user so it depends on how good they are.