Category: Press Releases

Professor Lyesse Laloui delivers the prestigious Vienna Terzaghi Lecture

© 2022 EPFL

The Vienna Terzaghi Lecture 2022 has been awarded to, and presented by, Professor Lyesse Laloui of EPFL at this year’s Austrian Geotechnical Conference on the 19th of April. Since 1997, the combined lecture and award have been given biennially to internationally renowned geotechnical engineers by the Association of Austrian Drilling, Well Construction and Foundation Engineering Companies (VÖBU), the Austrian Association of Engineers and Architects (ÖIAV), the Austrian National Committee (ASMGE) of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE) and the Institute of Geotechnics, Foundation Engineering, Soil and Rock Mechanics at the University of Vienna.

This year’s winner, Professor Laloui, is Chair Professor of Soil Mechanics and the European Vice President-elect of the International Society of Soil Mechanics and Geotechnical Engineering (ISSMGE). His lecture titled, “Tailor-made soil properties by bio-geochemical means” presented his latest research on the multiphysical analysis of bio-cementation processes in nature and their practical engineering applications.

The lecture is named in honor of Karl von Terzaghi, who is considered the founding father of soil mechanics, a field of engineering exploring the mechanics of soils and its application in geotechnical engineering. His radical work on the properties of soils led him to develop unifying concepts on earth pressure and slope stability.

© 2022 EPFL

Throughout his distinguished career, Professor Laloui has looked to apply and build upon the fundamentals that Karl Terzaghi developed. Terzaghi observed, “Rainfall-induced pore pressure hike is not the cause of landslides, but a contributing factor. There were many higher hikes in the geological past! The cause is long-term gradual, cumulative chemical weathering which weakens inter-granular bonds which leads to decrease of cohesion”.

These pioneering ideas became the foundational theory behind Laloui’s latest research project BIOGEOS, an ERC-funded exploration of the interaction between water and soils which, rather than decreasing the cohesion as described by Terzaghi, strengthens it through natural bio-cementation.

Author: Brendan Smith

Source: Soil Mechanics Laboratory

A novel use of hydrogel encapsulation of bacteria for on-demand release of MICP in soils

Interested in knowing how can we control the location and timing of the Microbially-Induced Calcite Precipitation (MICP) reaction, and the structure and properties of the resulting carbonate minerals?

Our new paper “Controlling the calcium carbonate microstructure of engineering living building materials”, published in the Royal Society of Chemistry Journal of Materials Chemistry A introduces a novel use of hydrogel encapsulation of bacteria for on-demand release of MICP in soils.

The methods developed bring together multidisciplinary expertise in soil mechanics, material science and biological processes from three different laboratories of EPFL: the Laboratory of Soil Mechanics (LMS) (Dr Alexandra Clarà Saracho, Lorenzo Lucherini, Dr Dimitrios Terzis and Prof. Lyesse Laloui), the Soft Matter Laboratory (Matteo Hirsch and Prof. Esther Amstad) and the Stream Biofilm and Ecosystem Research Laboratory (Dr Hannes M. Peter).

This work has received funding from a 2018–2024 European Research Council (ERC) Advanced grant awarded to Prof. Lyesse Laloui, who heads the LMS and is a co-author of the paper, under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 788587). The authors would also like to acknowledge the Gebert Rüf Stiftung (ref: GRS-027/19, EPFL grant number: 7683) innovation booster grant.

References

[1] https://pubs.rsc.org/en/content/articlelanding/2021/TA/D1TA03990C

[2] https://actu.epfl.ch/news/professor-laloui-awarded-a-prestigious-erc-advance/

[3] https://biogeos.epfl.ch/news/lyesse-laloui-awarded-a-prestigious-erc-proof-of-concept-grant/

Using electric current to stabilize low-permeability soils

EA MICP

EPFL scientists have developed a new approach to stabilizing clay soils. The method involves using a battery-like system to apply electric current to carbonate and calcium ions in order to promote soil consolidation. Their findings were published yesterday in Scientific Reports.

According to figures released by the UN yesterday, natural disasters have killed more than 1.2 million people since 2000 and cost nearly $ 3 trillion.These pressing threats bring into sharp focus the need for new answers to the problem of soil stabilization. Scientists at EPFL’s Laboratory of Soil Mechanics (LMS) have developed a number of sustainable solutions, including one that uses enzyme metabolism. Although these methods work for a wide range of soil types, they are considerably less effective when it comes to clay soils. In a paper published yesterday in Scientific Reports, the team demonstrates how chemical reactions can be enhanced by using a battery-like system to apply electric current.

A new type of biocement – produced in situ and at ambient temperature – has recently been put forth as a promising method for stabilizing various soil types. The method harnesses bacterial metabolism to produce calcite crystals that durably bond soil particles together. This biogeochemical process is energy-efficient and cost-effective, and could be rolled out quickly in the coming years. But since the ground needs to be impregnated for the method to work, it is less suited to low-permeability clay soils. Now, the LMS team has developed and successfully tested a viable alternative, which involves applying electric current using sunken electrodes. “Our findings show that this geoelectrochemical system does indeed influence key stages of the calcification process, especially the formation and growth of the crystals that bind the soil together and enhance its behavior,” says Dimitrios Terzis, a scientist at LMS and one of the co-authors of the paper.

The biocement is formed by introducing chemical species into the soil. These include dissolved carbonate and calcium ions, which carry opposite charges. Sunken anodes and cathodes are used to create an electric field, much in the same way as a giant battery. The current forces the ions to move across the low-permeability medium, where they intersect, mix together and eventually interact with soil particles. The result is the growth of carbonate minerals, which act as links or “bridges” that enhance the mechanical performance and resistance of soils.

Technology transfer grant

The paper, which sets out the team’s findings from observing and measuring the quality of these mineral bridges, paves the way for future developments in the field. Further tests, at different scales, are needed before the technology can be applied in the real world. The research was carried out under a 2018–2023 European Research Council (ERC) Advanced grant awarded to Prof. Lyesse Laloui, who heads the LMS and is a co-author of the paper. The project has three verticals, targeting the understanding of the fundamental mechanisms that occur at the soil-particle scale (micro-scale), the advanced characterization of mechanical behaviors at laboratory scale, and the large-scale development and demonstration of innovative systems in natural environments. In July 2020, the same research team obtained an additional ERC Proof of Concept grant to accelerate technology transfer to industrial applications.

In the past, soils were treated solely as a mix of solid earth, air and water. According to the co-authros, this research highlights how cross-disciplinary approaches i.e., drawing on concepts from biology and electro-chemistry and incorporating advances and mechanisms from other scientific fields can open exciting new paths and yield significant benefits.

References

[1] https://www.nature.com/articles/s41598-020-73926-z 

[2] https://ec.europa.eu/jrc/en/news/critical-infrastructure-be-hard-hit-climate-hazards

[3] https://actu.epfl.ch/news/professor-laloui-awarded-a-prestigious-erc-advance/

[4] https://biogeos.epfl.ch/news/lyesse-laloui-awarded-a-prestigious-erc-proof-of-concept-grant/

Source: EPFL homepage

Lyesse Laloui awarded a prestigious ERC Proof of Concept Grant

PoC

Accelerating technology transfer and coupling scientific, industrial and environmental advances.

Lyesse Laloui, professor at EPF Lausanne and director of the Soil Mechanics Laboratory is awarded the prestigious Proof of Concept Grant (PoC) by the European Research Council (ERC). The grant adds up to the breakthrough developments achieved within the first 18 months of his previous advanced ERC-funded BIOGEOS project which is developing novel bio-cementation technologies for civil, geotechnical and geo-environmental works. The ERC PoC grant further validates the technology-transfer vision of the BIOGEOS project and accelerates its aim to develop complete and industry-ready solutions to serve infrastructure, economic and societal needs.

ERC Proof of Concept (PoC) Grants provide lump-sum funding to academics who have demonstrated breakthrough advances towards exploring the societal and economic potential of their discoveries. By providing additional resources, the grants consolidate the achievements of ERC-Advanced grants, funded under the EU’s research and innovation programme, Horizon 2020.

CEBREWA builds up on the achieved breakthroughs of BIOGEOS

CEBREWA (Construction & Environmental Biocementation in REal World Applications) tackles the emerging ground stabilisation problems which are becoming increasingly pressing in construction and environmental engineering. Ground stabilization mitigates stability risks associated with geohazards, such as earthquakes, soil erosion, and landslides. Such problems are expected to be further intensified by extreme weather and aging infrastructure. Traditionally, ground stabilization is applied to roads, railroads, airfields, embankments, reservoirs, bank protection, canals, dams, and coastal engineering. Rapid urbanization, particularly in developing regions, is fueling the ground stabilization market growth. This is primarily due to: (i) the scarcity of suitable land for development and (ii) the need to extend existing infrastructure (typically by building more floors, and therefore increasing the loads sustained by foundations) to support increasing populations in urban zones. The market of ground stabilization has not been disrupted for decades, with current solutions complex and expensive, mainly due to the heavy equipment required for their application, and often hazardous to the environment, as they rely on the extensive use of industrial fluids or microplastics. The latter is especially prevalent in polyurethane-based solutions, which are currently used as expansive polymer foams in foundation repair works. Another problematic aspect of existing solutions is related to the level of energy required on-site to generate the high pressures required to inject the above stabilizing agents into the ground. Further, from an environmental perspective, existing fly ash-, lime-, and cement-based solutions generate pH-levels above 12. Such conditions are above the typical values of soil pH, and they cause irreversible damage to the groundwater and subsurface ecosystem. Therefore, a market gap exists, and CEBREWA aims to fill it with the innovative ground bio-stabilization solutions based on innovative carbonate biomineralization which is developed and patented during BIOGEOS.

Further information

Source: Soil Mechanics Laboratory

Official kick-off for BIOGEOS at EPFL

Official kick-off for BIOGEOS at EPFL

BIOGEOS logo

November 1st marks the official launch of BIOGEOS (Bio-mediated Geo-material Strengthening). BIOGEOS receives funding from the European Research Council (ERC) under an ERC Advanced Grant (grant agreement no 788587). The grant is awarded to Prof. Lyesse Laloui, head of the Soil Mechanics Laboratory (LMS) of the Swiss Federal Institute of Technology, Lausanne (EPFL). BIOGEOS explores bio-mediated ground improvement, within the broader framework of multiphysical processes in sustainable Geotechnics. Its overarching goal is to establish a new paradigm in research and development for geo-technical applications, by developing, delivering and mastering nature-inspired solutions for real-world geotechnical problems. Within the project’s mission are the design, testing and ultimately standardization of innovative solutions, which combine techno-economic efficiency with environmental responsibility.

Coordinator: Prof. Lyesse Laloui

Host Institution: Swiss Federal University of Technology, EPFL

Timeframe: 5 years (1/11/2018-31/10/2023)

Budget: ca. 2.5 M €

Website: biogeos.epfl.ch

e-mail: biogeos@epfl.ch

Twitter: @biogeosH2020