Biogeochemical processes and geotechnical applications: progress, opportunities and challenges

TLDR

Viewing soil as a living ecosystem introduces a new paradigm that offers innovative, sustainable solutions to geotechnical problems through biomediated geochemical processes such as mineral precipitation, gas generation, biofilm formation, and biopolymer production. The paper evaluates the progress, opportunities, and challenges of this multidisciplinary paradigm for beneficial ground modification. The authors describe a multidisciplinary approach that uses subsurface microbial processes to create favorable conditions for geochemical reactions, while highlighting challenges such as scaling to field, monitoring, modeling, by‑product management, durability, and engineering education. Current applications of biomediated ground modification include sand cementation for bearing capacity and liquefaction resistance, carbon sequestration, erosion control, groundwater flow control, and remediation of metal‑ and radionuclide‑contaminated soil and water.

Abstract

Consideration of soil as a living ecosystem offers the potential for innovative and sustainable solutions to geotechnical problems. This is a new paradigm for many in geotechnical engineering. Realising the potential of this paradigm requires a multidisciplinary approach that embraces biology and geochemistry to develop techniques for beneficial ground modification. This paper assesses the progress, opportunities, and challenges in this emerging field. Biomediated geochemical processes, which consist of a geochemical reaction regulated by subsurface microbiology, currently being explored include mineral precipitation, gas generation, biofilm formation and biopolymer generation. For each of these processes, subsurface microbial processes are employed to create an environment conducive to the desired geochemical reactions among the minerals, organic matter, pore fluids, and gases that constitute soil. Geotechnical applications currently being explored include cementation of sands to enhance bearing capacity and liquefaction resistance, sequestration of carbon, soil erosion control, groundwater flow control, and remediation of soil and groundwater impacted by metals and radionuclides. Challenges in biomediated ground modification include upscaling processes from the laboratory to the field, in situ monitoring of reactions, reaction products and properties, developing integrated biogeochemical and geotechnical models, management of treatment by-products, establishing the durability and longevity/reversibility of the process, and education of engineers and researchers.