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Iowa State University--Becoming the Best

Use of Biocementation for Slope Stabilization of Levees

Researcher(s)

Principal investigator:

Co-principal investigators:

Project status

In progress

Start date: 09/01/16
End date: 08/31/17

Sponsor(s)/partner(s)

Sponsor(s):

About the research

Abstract:

While levee embankments are the first line of defense for urban flooding, recent flooding events have revealed the widespread issue of slope instability of embankments around the country that lead to levee failures. This proposed work aims to improve the slope stability of earthen levees by soil strengthening through the use of a biologically-inspired technique called biocementation.

The major objective of this proposed study is to determine the optimal and most practical biocementation method that results in the best performance of levee slopes under various flooding conditions. Two biocementation methods will be tested: microbiologically-induced calcite precipitation (MICP) and enzyme-induced calcite precipitation (EICP). These methods differ mainly in the size of the biological agent (whole bacterial cell versus enzyme) and, thereby, their mobility in soils of different grain sizes.

The MICP and EICP methods for soil strengthening will be optimized in laboratory-scale column experiments. The optimized methods will then be used to construct levees in an experimental flume system. The performance of these strengthened levees will be tested under varying hydrological conditions, including normal, overtopping, and flooding scenarios.

This study will provide data-driven comparisons between MICP and EICP methods and will determine the most appropriate method for the improvement of levee slope stability. The results of this study will help mitigate flooding events that could cause major issues in transportation infrastructure and traffic safety.