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(slow instrumental music)

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(mechanical noise)

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- [Narrator] Core sampling
has been the way road builders

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and bridge engineers determine

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the subsurface soils on a planned project.

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However, the information is not complete

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and the core samples often miss

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a drastic change in soil
conditions between the samples.

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The misdiagnosis can be costly.

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So researchers with the
University of Texas at Arlington

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have investigated a new technique

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called Electrical Resistivity Imaging

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to help fill in the gaps.

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- Texas faces many cost
overruns and change orders.

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And many of these costs
overruns and change orders

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of project, are due to

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lack of sufficient subsurface information.

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- For any infrastructure
project, a road or a bridge.

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Before we can design it,
we have to figure out

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what's going on with
the ground underneath it

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and traditionally we would drill,

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we would get borings where we drill down,

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either run tests in
situ or sample the soil,

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take it back to the lab and
measure engineering properties.

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It's fairly expensive.

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There's only so many borings,

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you can do for any given job site.

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- It's kind of a hit or miss approach

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and so we may be missing a very critical

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element of what's underneath,

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and if we have missed it
during our investigation,

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would definitely have
to pay for that during

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the building of our
infrastructure, or we have to pay,

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We're basically deferring that to when it,

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when that structure fails.

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- [Trenton] This research
project enables Tex Dot

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to do more with a geophysical method

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called electrical resistivity imaging.

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- [Moshen] What you get
from these technologies

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is a bunch of numbers and images,

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which is telling you what
the electrical resistivity

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in the ground is.

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But it doesn't relate
that information to soil.

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So what we did is, we basically
visited five districts.

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We collected soil samples
and those soil samples,

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we brought all of them to our labs.

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In our lab, we did lots of testing,

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electrical resistivity testing,

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and many of the geo-technical,
basically, testing.

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Then, using this information,
we created a manual

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and in that manual, we explained

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that how electrical
resistivity should be done.

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And we included equations and charts

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that they are establishing
relationships between

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electrical resistivity results
and geo-technical parameters

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that we use in our designs.

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We also included information
of how to interpret

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electrical resistivity images.

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- During our planning phase,

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we have to go through
our environmental process

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and schematic development that includes

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alternative analysis for at
least two or three alternatives.

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And this technology will give us

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preliminary information
on what's underneath.

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Under the footprint of each alternative.

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In that way, we'll be able to decide

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if some of the alternatives
are better than the others.

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- We're basically bringing
subsurface site investigations

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into the 21st century.

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We're very good at leveraging
the traditional methods

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of site exploration, but
now we are leveraging

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more advanced methods.

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- [Narrator] For more information,

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and to find the publications
for this project,

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please visit the Tex Dot research library

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at the link shown below.