KOIN: Making soil stronger: A new way to prep for The Big One
Author: Elise Haas
Posted: September 13, 2019

To read the original story, visit KOIN.

The Portland area is surrounded by 2 major rivers. In a large earthquake that means the soil could liquify, making the soil unstable and causing widespread damage.

Portland State University professors along with civil engineers from other universities are testing a new treatment to prevent that from happening.

Liquefaction, as it’s called, is a phenomenon during earthquakes that turns the ground into a soup of water and soil that would allow structures on top to collapse and sink. Obviously, that would threaten Portland’s buildings, bridges, dams, fuel tanks and airports.

“Just the economic impact of that is huge,” said PSU Assistant Professor of Civil Engineering Arash Khosravifar.

“We’ll come out and try to study soils that are problem soils,” said Ken Stokoe, a professor of civil engineering with the University of Texas.

The testing underway — the first field test of its type in the US — will check a way to mitigate the liquefaction by strengthening the soil.

“We use the microrganisms in the soil to desaturate the soil to the point the soil would not liquify anymore,” Khosravifar told KOIN 6 News.

Stokoe said they’ve pushed sensor down into the ground to measure motion and water pressure.

While earthquake shakers simulate a quake, students record data to test if the soil is stronger. So far, they’ve been desaturating the soil in Northeast Portland near the Portland International Airport for a month.

They’ll continue to test for the next few years to see how the ground holds up. With this new approach, liquefaction could be mitigated at a fraction of the cost of previous methods — which could change the way Oregon prepares for and recovers from The Big One.

“If it is effective,” Khosravifar said, “it could be a game changer.”