Technologies Cost-Effectively Limit Earthquake Soil Liquefaction

Achievement date: 
2016
Outcome/accomplishment: 

The NSF-funded Engineering Research Center (ERC) for Bio-mediated and Bio-inspired Geotechnics (CBBG), headquartered at Arizona State University, is developing three technologies that use precipitation of calcium carbonate for cost-effective remediation of soil liquefaction. The technologies curtail the impact of earthquakes that cause soil to rapidly lose firmness and act like a liquid.

Impact/benefits: 

These technologies improve upon existing techniques that induce ground movements that can damage nearby infrastructure. Less disruptive techniques are either expensive, burdensome to apply, or have limited applicability. This advance can prevent and lower the human and monetary costs of future earthquakes from liquefaction-induced damage to infrastructure worth trillions of dollars.

Explanation/Background: 

These technologies can improve earthquake safety and remediation in the approximately 40 percent of the U.S. that the latest National Seismic Hazard Map for ground motions has identified as having a 90 percent chance of in the next 250 years of experiencing earthquakes that could trigger soil liquefaction.

The Center developed three ways to use precipitation of calcium carbonate, preferably in the form of calcite, to improve granular soil and its resistance to liquefaction. These are: microbially-induced carbonate precipitation (MICP) by stimulating native microbial communities; enzyme-induced carbonate precipitation (EICP), which uses an agriculturally-derived enzyme; and microbially-induced desaturation and precipitation (MIDP)—the least mature of the three technologies—which also relies on the stimulation of native microbes. Each process has advantages and limitations, and researchers’ evolving understanding suggests that each process may have a role in geotechnical practice.