Seeking an Underground View
January 5, 2012
Hanover uses the Seeker SPR to analyze the subsurface rock, instead of boring holes every 30 feet.
When
Hanover Engineering began work on a 20-mile long sewer project estimated at $18
million, they knew it wouldn’t be easy, especially due to the subsurface rock
on the trench lines.
Typically, analyzing this kind of rock requires boring test holes approximately
every 30 feet—a tedious and time-intensive approach. Using this traditional
method, it would have meant that the team needed to bore more than 3,500 holes
for analysis as part of the project in Ephrata, Pa. When a project grant
restricted the timeline for the East Coast firm, they knew they needed to
search for a faster, more modern method of tackling the work.
“I felt we needed to find some type of system, some type of equipment, that
could survey so we could try to analyze the amount of rock on these trench
lines,” says Matthew Epler, engineer-in-training with Hanover’s Ephrata, Pa.,
office.
Relying on Radar
The firm’s research turned up US Radar, and Hanover Engineering tested and
purchased the company’s wheel-mounted Seeker SPR (subsurface penetrating radar)
with a 500-megahertz antenna. Crews simply push the Seeker over the surface of
the trench area, relying on its subsurface penetrating radar system to do the
work for them and display the results on the touch screen
panel.
According to Ron LaBarca, president of US Radar, the Seeker transmits energy
pulses through various types of surfaces, including clay, soil, concrete and
brick. Whether the depth range on the project is known or not, the Seeker
produces images of what’s below and can tailor the picture based on a user’s
set parameters, such as soil settings, algorithms and color palette. Everything
is displayed on a large, bright screen that’s easily visible even in daylight,
LaBarca says.
“It’s like looking at an X-ray,” Epler says. “The more you look, the more you
see.”
The 500-megahertz antenna that Hanover chose is among the most popular of the
frequency options US Radar offers, LaBarca says. The full range extends from
100- to 2,000-megahertz. The Seeker works best at 100 megahertz for detecting
sizable objects, such as bedrock and large pipes at depths of up to 100 feet.
On the opposite end, the 2,000-megahertz antenna provides high-resolution
details at depths to 18 inches, displaying everything from fine wire to cracks
in concrete. The 500-megahertz antenna provides good versatility, LaBarca says,
with up to 14 feet of detection for pipes, cables and soil disturbances.
The Seeker transmits energy pulses through various types of surfaces, including clay, soil, concrete and brick.
According to LaBarca, more than 50,000 lineal feet of data can be collected and stored in the Seeker before being transferred via USB port to a Windows-based operating system that processes and filters the information.
Though it might not be typical to think of a data tool as “rugged,” that is the case with the Seeker SPR, LaBarca says. All of the machine’s cables and connections have been constructed with tough military-specification, waterproof connectors. Two sturdy wheels scientifically balance the equipment for stability, he says, which also minimizes the pushing effort and, in conjunction, operator fatigue. Additionally, an optional rough terrain attachment with two additional tires makes the machine ready to traverse almost any surface condition. The Seeker also works silently by operating off of a battery that provides four to six hours of continuous run time.
GPS Option Available
Epler estimates the Seeker cut the time needed to survey the area by 70 percent. Plus, it reduced concerns about impacting the environment that they could have faced on a project that requires thousands of bore holes. Epler says the crew will just do a few bore holes to confirm the data the Seeker provided.
“We’ll take this data we received from the US Radar equipment, and we can take it to be very selective on the boring,” Epler says.
Beyond the sewer pipe project, Hanover anticipates its Seeker SPR will be beneficial in other engineering applications, from finding sinkholes to locating storm pipes for clients. It has already been used to locate water lines and water services, as well as explore tight spaces to avoid conflicts between existing utilities and proposed new utilities. Hanover is now looking into adding a GPS option with the Seeker, which can be attached to an external GPS device for additional data collection.
“(The GPS option is) one we’re very interested in and one we’d get a good amount of use from,” Epler says. “It can tell us exactly where we’re at, where the scans start and stop. This would be a time-saving feature and just help make the process more precise.”
Overall, Epler says the Seeker provides an accurate, real-time picture of what lies beneath—whether that’s wires, bedrock or large pipes—all without disturbing the surface or consuming valuable time like other methods.
“I would honestly go as far as saying this equipment is a survey tool,” Epler says. “Obviously it’s not the answer to everything, as no one piece of equipment is, but it’s a very good survey tool to have in the toolbox.”
Company: Hanover Engineering
Location: Ephrata, Pa.
Project: Analyzing subsurface rock on 20-mile sewer project
Equipment Used: US Radar Seeker SPR
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