Ground Modification using Microbially Induced Desaturation (MID) for Liquefaction Interim Risk Reduction

Project ID: 23020
Principal Investigator: Angel Gutierrez
Research Topic: Repair and Maintenance
Funded Fiscal Years: 2023 and 2024
Keywords: None

Research Question

1. Can MID provide liquefaction interim risk reduction for Reclamation facilities?
Problem: Liquefaction issues at Reclamation facilities tend to have significant costs and/or require more advanced analyses which require an interim risk reduction while a permanent solution is found.
Hypothesis: MID will provide a significant liquefaction risk reduction in a cost-effective manner with minimal disruption to existing facilities.

2. What is the durability of MID in different soil types?
Problem: Published MID work is mostly on homogenous, lab soils.
Hypothesis: MID will be persistent in soil types ranging from coarse silt to fine gravel, for periods of several years, or longer.

3. Can MID treatment be applied uniformly in stratisfied soil?
Problem: MID reagents may not distribute uniformly if a treatment area is comprised of stratified soil.
Hypothesis: Permeability differences will result in MID reagents being distributed within the zones that are most susceptible to liquefaction.

4. Are all liquefiable soils amenable to MID treatment?
Problem: The range of soil subject to MID testing in the laboratory is limited.
Hypothesis: Local water and soil chemistry will play a part in the effectiveness of MID as a liquefaction mitigation measure.

5. What in-field methods can be implemented to verify desaturation of in-situ soils?
Problem: There is no industry standard for verifying the effectiveness of MID.
Hypothesis: Geophysical methods, such as seismic refraction & reflection or electrical resistivity can verify the effectiveness of MID.

6. Is MID a cost-effective interim risk reduction measure for liquefaction?
Problem: Liquefaction interim risk reduction measures tend to have a high socioeconomic cost. New methods must be competitive or offer a significant improvement to current standards.
Hypothesis: MID will provide a new, cost-effective method for liquefaction interim risk reduction that will not require major operational restrictions on applicable projects.

Need and Benefit

The most common interim risk reduction measure for projects where liquefaction has been identified as a potential failure mode needing to be mitigated is the removal of liquefiable materials which can be costly and invasive to the facility. Another interim risk reduction measure for liquefaction concerns is a reservoir restriction in the case of a dam, or a flow restriction in the case of a canal. These restrictions can last months to years, resulting in diminished storage capacity, reduced water deliveries, a reduction in power generation, and the loss of recreational opportunity. The development of new technologies that provide an interim fix without operational impact is key for Reclamation in this time of drought.

If this project were not funded, Reclamation would continue to rely on other liquefaction risk-mitigating methods that are costly (i.e. material removal), partially effective or have significant operational impacts that can be detrimental to water deliveries (i.e. reservoir elevation restrictions). These operational impacts are particularly of concern with current drought conditions throughout the Western U.S. This work could have direct benefit for Ochoco and other dams, as well as the All-American Canal and its distribution system.

The goal of this project is to leverage the expertise of a broad swath of partners to further the development of MID/P as a liquefaction mitigation technology. The incorporation of technology improvements through targeted laboratory testing along with developing a draft risk analysis framework provides a uniquely robust research strategy that can lead to rapid adoption and immediate/future benefits. The immediate benefit of this research is to lay a framework for future field-scale implementation. Underlying questions about dosing, migration through layered stratigraphy, efficacy, verification, and incorporation of findings into Reclamation's risk framework will all be answered directly by this research. The research will also quantify seepage reduction and the associated potential cost savings versus typical lining systems.

The future benefit and impact of the technology is a tool outside of a reservoir restriction and other costly mitigation methods to provide an interim risk reduction measure that will not have an impact on operations. The desaturation will also have an immediate secondary impact in reducing seepage losses. Long-term, by including the risk framework with the lab testing, the outcome of the research lays a solid framework for incorporating this technology at the small canal or ditch scale, all the way up to large embankment dams. The additional benefit of seepage reduction will result in immediate water loss reductions and cost savings for Reclamation. Increased water deliveries will benefit irrigation districts and other stakeholders.

The technology is a better option than a reservoir restriction as operations would not be limited once a liquefaction potential failure mode is identified. This would allow uninterrupted deliveries or increased water deliveries resulting in a cost-savings to Reclamation. The technology could be a long-term liquefaction mitigation and seepage reduction modification for many smaller structures. For liquefaction mitigation, it is anticipated to be significantly cheaper than current filter and berm fixes. MID/P would also be significantly cheaper than typical canal lining technologies. In these cases, the BCR when compared to current technology would be significant.

Contributing Partners

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Research Products

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Last Updated: 6/22/20