This week CEE’s very own Dr. Michael Gomez will speak about his newly funded NSF CAREER grant that aims to improve bio-cementation by using biological processes to strengthen soils against earthquake-induced liquefaction.
The talk is entitled “Bio-cementation: Soil Improvement for the Mitigation of Earthquake-induced Soil Liquefaction.” Join on Thursday, April 15 at 3:30 pm PST through this zoom link.
Check out the presentation abstract by continuing to read.
Presentation Abstract:
Recent advances in bio-mediated soil improvement technologies have highlighted the potential of natural biological/chemical reactions in the soil subsurface to enable mitigation of infrastructure damage resulting from natural hazards such as earthquakes. Bio-mediated geotechnical solutions leverage the capabilities of microorganisms already existing in the geotechnical subsurface to generate a diverse range of “products”, which can dramatically improve the engineering behavior of soils. One such technology, Microbially Induced Calcite Precipitation (MICP), is an environmentally conscious soil improvement technique that can improve the geotechnical properties of granular soils through the precipitation of calcite. The biogeochemical process offers an environmentally-conscious alternative to traditional brute-force mechanical and Portland cement based ground improvement methods, by utilizing natural microbial enzymatic activity to induce calcite precipitation on soil particle surfaces and at particle contacts.The resulting bio-cementation affords improvements in soil shear strength, initial shear stiffness, and liquefaction resistance, while reducing soil hydraulic conductivity and porosity. Although MICP has been demonstrated extensively at the laboratory scale, critical gaps remain in our understanding of this technology with respect to up-scaling the process to field-scale, understanding the engineering behavior of (bio-)cemented geomaterials, and evaluating material permanence. This presentation will provide a brief introduction to MICP and highlight results from several recent experiments completed at centimeter- and meter- scales aimed at: (1) developing the MICP process for field-scale deployment including techniques for (i) the stimulation of indigenous microorganisms, (ii) management of ammonium by-products, and (iii) improvement of cementation spatial uniformity and extent, (2) characterizing the liquefaction resistance of bio-cemented geomaterials, and (3) systematically exploring the effect of treatment conditions and environmental factors on resulting material mineralogy and long-term permanence.