| Void
and cavity location and scanning |
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Void and cavity location with Geophysics requires experience, a good
understanding of the targets and a systematic approach |
Download
Application Notes |
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This is an example of a class A RVS. The reader
can see the negative or “black” pulse at the top of the target and
the weaker but evident positive reflection at the base of this
target.
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Subsurface Imaging in action
locating voids under concrete slabs
Extensive test boring had shown
some cavities but it was much quicker and easier to do GPR. |
Setting up this grids over the probable cavities
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The NDT methods to locate the cavities meant quick results , no drilling and precise
location of the problem areas. |
Collecting the data |
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In addition this also meant the survey can be rerun to check void
development over a longer interval. |
Checking the layout |
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The output is from the survey in
the pictures. It is a fine grid of data where the Ground Radar lines
are run in two directions at right angles with a spacing of 0.5 m. Processing
involves combining all these together. The output is a horizontal
slice to give plan view images that are hereThe result... The red and yellow areas are the
voids.. The green shows no voids. These were checked by lifting test
slabs to check and the correlations were within cm for the void
edges |
Plan View of GPR data
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| Download
Application Notes |
SUCCESS |
| We have achieved similar results
with a variety of geophysical methods, Radar, EM, Electrical
Resistivity Imaging, Cross-hole surveys
Talk to SSI about your void
imaging or location issue
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email or
Phone Link to Information Request Form
Radar Basics (to get you started)--click
through to follow link
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