Bacteria Could Steady Buildings Against Earthquakes

Feb 21, 2007

Soil bacteria could be used to help steady buildings against earthquakes, according to researchers at UC Davis. The microbes can literally convert loose, sandy soil into rock.

When a major earthquake strikes, deep, sandy soils can turn to liquid, with disastrous consequences for buildings sitting on them. Currently, civil engineers can inject chemicals into the soil to bind loose grains together. But these epoxy chemicals may have toxic effects on soil and water, said Jason DeJong, an assistant professor of civil and environmental engineering at UC Davis.

The new process, so far tested only at a laboratory scale, takes advantage of a natural soil bacterium, Bacillus pasteurii. The microbe causes calcite (calcium carbonate) to be deposited around sand grains, cementing them together. By injecting bacterial cultures, additional nutrients and oxygen, DeJong and his colleagues found that they could turn loose, liquefiable sand into a solid cylinder.

"Starting from a sand pile, you turn it back into sandstone," DeJong said. Similar techniques have been used on a smaller scale, for example, to repair cracks in statues, but not to reinforce soil.

The new method has several advantages, DeJong said. There are no toxicity problems, compared with chemical methods. The treatment could be done after construction or on an existing building, and the structure of the soil is not changed -- some of the void spaces between grains are just filled in.

DeJong and his collaborators are working on scaling the method up to a practical size, and applying for funds to test the method in the earthquake-simulating centrifuge at UC Davis' Center for Geotechnical Modeling. The centrifuge is part of the national Network for Earthquake Engineering Simulation, funded by the National Science Foundation.

A paper describing the work has been published in the Journal of Geotechnical and Geoenvironmental Engineering.

Source: UC Davis

Explore further: A smart prosthetic knee with in-vivo diagnoses

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

A smart prosthetic knee with in-vivo diagnoses

Apr 22, 2014

The task was to develop intelligent prosthetic joints that, via sensors, are capable of detecting early failure long before a patient suffers. EPFL researchers have taken up the challenge.

Old tires become material for new and improved roads

Apr 22, 2014

(Phys.org) —Americans generate nearly 300 million scrap tires every year, according to the Environmental Protection Agency (EPA). Historically, these worn tires often end up in landfills or, when illegally ...

Students take clot-buster for a spin

Apr 21, 2014

(Phys.org) —In the hands of some Rice University senior engineering students, a fishing rod is more than what it seems. For them, it's a way to help destroy blood clots that threaten lives.

User comments : 0

More news stories

SK Hynix posts Q1 surge in net profit

South Korea's SK Hynix Inc said Thursday its first-quarter net profit surged nearly 350 percent from the previous year on a spike in sales of PC memory chips.

FCC to propose pay-for-priority Internet standards

The Federal Communications Commission is set to propose new open Internet rules that would allow content companies to pay for faster delivery over the so-called "last mile" connection to people's homes.

Brazil enacts Internet 'Bill of Rights'

Brazil's president signed into law on Wednesday a "Bill of Rights" for the digital age that aims to protect online privacy and promote the Internet as a public utility by barring telecommunications companies ...

Phase transiting to a new quantum universe

(Phys.org) —Recent insight and discovery of a new class of quantum transition opens the way for a whole new subfield of materials physics and quantum technologies.

Imaging turns a corner

(Phys.org) —Scientists have developed a new microscope which enables a dramatically improved view of biological cells.