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: Lifting the brakes on fuel efficiency

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Lifting the brakes on fuel efficiency

Apr 18, 2014

The work of a research leader at Michigan Technological University is attracting attention from Michigan's Governor as well as automotive companies around the world. Xiaodi "Scott" Huang of Michigan Tech's ...

Large streams of data warn cars, banks and oil drillers

Apr 16, 2014

Better warning systems that alert motorists to a collision, make banks aware of the risk of losses on bad customers, and tell oil companies about potential problems with new drilling. This is the aim of AMIDST, the EU project ...

User comments : 0

More news stories

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Under some LED bulbs whites aren't 'whiter than white'

For years, companies have been adding whiteners to laundry detergent, paints, plastics, paper and fabrics to make whites look "whiter than white," but now, with a switch away from incandescent and fluorescent lighting, different ...