GPR for Soil Testing and Environmental Surveys

Why is Soil Testing Important?

Starting construction on a major commercial project can be daunting, especially when it comes to testing the soil of the future construction site or existing industrial site.

Traditionally, environmental scientists would rely on the destructive drilling and excavating of 1-2 boreholes (for a small site) to 30 boreholes (for a large site).

Each borehole averages $5,000-$10,000 — making soil sampling a very pricey project, indeed.

Ground-penetrating radar (GPR) is becoming the preferred method of soil testing and surveying, leading to fewer comparison boreholes and a more comprehensive view of the construction site. It’s a far less expensive and safer way to do a quick, noninvasive survey than to drill numerous holes in the ground.

Without soil testing or GPR, many sites have ended up falling victim to bad foundations, including the famous leaning tower of Pisa in Italy. It was designed to stand 60 meters, but now leans 4 degrees because of poor foundation.

Soil testing could have provided information crucial to the tower’s success: bearing capacity, density, compaction, sand and contaminants.

When soil is contaminated, it often needs to be removed. That’s when GPR comes in handy at sites like old gas stations and industrial sites to landfills.

What Can GPR Detect?

GPR surveys can help detect oil reservoirs, deteriorating underground storage tanks, gas leaks, contaminated soil, sinkholes and voids, — as well as waste drums filled with chemicals that were routinely dumped in the 1970s and 1980s. 

If soil contamination is present, it can be dangerous for excavation crews, not to mention a liability to the entire project.

Many underground storage tanks were designed for fuel storage, back when oil was used to heat Texas homes and commercial buildings. Underground storage tanks can also hold septic waste, propane and fast food grease.

GPR maps the entire tank and can reveal if a tank has external punctures or severed connections. A soil test provides analysis to help clean up any leaks.

The GPR antenna system is able to detect leaks and soil contamination by contrasting electrical properties of both clean and contaminated soil, which is usually easier in dry soil rather than moist soil.

One study compared the GPR findings of three different sandy soils (landfill leachate, salt solution or diesel oil) and found that the soils showed different characteristics in the GPR profile.

Not only can GPR identify contaminated soil, it can also plot the extent of the contaminant plumes and determine which way the contaminant may be spreading.

Recent Soil Boring Inspections by Wood

Wood Inspection Services often partners with engineering firms, project managers and surveyors to conduct GPR scanning before soil tests are performed.

Our mapping process and equipment are comprehensive. Uncover specifics on soil and underground hazards at your site so you can get back to what you really want to do — build!

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