Bacteria Could Steady Buildings Against Earthquakes

February 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

Related Stories

Recommended for you

Netherlands bank customers can get vocal on payments

August 1, 2015

Are some people fed up with remembering and using passwords and PINs to make it though the day? Those who have had enough would prefer to do without them. For mobile tasks that involve banking, though, it is obvious that ...

Power grid forecasting tool reduces costly errors

July 30, 2015

Accurately forecasting future electricity needs is tricky, with sudden weather changes and other variables impacting projections minute by minute. Errors can have grave repercussions, from blackouts to high market costs. ...

Microsoft describes hard-to-mimic authentication gesture

August 1, 2015

Photos. Messages. Bank account codes. And so much moreā€”sit on a person's mobile device, and the question is, how to secure them without having to depend on lengthy password codes of letters and numbers. Vendors promoting ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.