Use of Biocementation for Slope Stabilization of Levees

While levee embankments are the first line of defense for urban flooding, recent flooding events have revealed widespread slope instability of embankments around the country that can lead to levee failures. This work aimed to improve the slope stability of earthen levees by strengthening the soil through the use of a biologically-inspired technique called biocementation. The major objective of this study was to determine the optimal and most practical biocementation method that results in the best performance of levee slopes under various flooding conditions. A novel biocementation method called bacterial enzyme-induced calcite precipitation (BEICP) was tested. This method differs from the well-studied microbial-induced calcite precipitation (MICP) method mainly in the size of the biological agent (whole bacterial cell vs. enzyme), which influences the agent’s mobility in soils of different grain sizes. The BEICP methods for soil strengthening were optimized in laboratory-scale column experiments. The optimized methods were then used to construct levees in an experimental flume system. The results indicated that the BEICP treatment resulted in significant strengthening of the surface of the soil specimens, which were measured as increases in unconfined compressive strength. The strengthened samples were able to resist erosion for a longer time period under overtopping scenarios of water challenges with high water velocity in a flume. Therefore, BEICP offers a sustainable and economical method for treatment of soil surfaces to improve erosion resistance. The results of this study will help mitigate flooding events that could cause major issues in transportation infrastructure and traffic safety.

Language

English

Project

Status: Completed
Funding: $162233
Contract Numbers:
DTRT13-G-UTC37
Sponsor Organizations:
Midwest Transportation Center

Iowa State University
2711 S Loop Drive, Suite 4700
Ames, IA United States 50010-8664

Office of the Assistant Secretary for Research and Technology

University Transportation Centers Program
Department of Transportation
Washington, DC United States 20590

Iowa State Universtiy

Civil, Construction, and Environmental Engineering
394 Town Engineering
Ames, Iowa United States 50011
Managing Organizations:
Iowa State University, Ames

Institute for Transportation
2711 South Loop Drive, Suite 4700
Ames, Iowa United States 50010-8664
Performing Organizations:
Iowa State University, Ames

Institute for Transportation
2711 South Loop Drive, Suite 4700
Ames, Iowa United States 50010-8664
Principal Investigators:
Ikuma, Kaoru

Cetin, Bora

Rehmann, Chris

Ong, Say Kee
Start Date: 20160901
Expected Completion Date: 20181130
Actual Completion Date: 0

Subject/Index Terms

TRT Terms: Flood protection; Infrastructure; Levees; Slope stability; Soil stabilization
Subject Areas: Bridges and other structures; Highways; Hydraulics and Hydrology; Materials; Safety and Human Factors;

Filing Info

Accession Number: 01618658
Record Type: Research project
Source Agency: Midwest Transportation Center
Contract Numbers: DTRT13-G-UTC37
Files: UTC, RIP
Created Date: Dec 2 2016 12:23PM