Ifsttar PhD subject

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Title : Amélioration des sols liquéfiables par bio-précipitation

Main host Laboratory - Referent Advisor   -

Director of the main host Laboratory   -

PhD Speciality Mécaniques des sols

Axis of the performance contract 2 - COP2017 - More efficient and resilient infrastructure

Main location Marne-la-Vallée

Doctoral affiliation ECOLE CENTRALE NANTES

PhD school Sciences de l'Ingénierie et des Systèmes (SIS)

Planned PhD supervisor SEDRAN Thierry  -    -

Planned financing cdd  - Ifsttar

Abstract

Soil liquefaction occurs when a saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress such as shaking during an earthquake or other sudden change in stress condition, in which material that is ordinarily a solid behaves like a liquid. To avoid liquefaction, soil densification is often used by various methods.
The approach in this study will be based on the internal enhancement by bio-precipitation of calcium carbonates by bacteria. Bioprecipitation is a natural phenomenon that can involve prokaryotic microorganisms according to the following reaction:

Ca2 + +2 HCO3- → CaCO3 + CO2 + H2O

After determining the bioprecipitation conditions, the improvement of the mechanical properties of soils by bio-precipitation of calcium carbonates will be examined in this study by: 1) measurements of shear wave velocity (P -RAT) throughout the entire process and 2) by performing cyclic tests on improved and unimproved samples using a single device (TxSS)

Keywords : Soil mechanics, liquefaction, bio-precipitation, Soil consolidation

Main host Laboratory - Referent Advisor	-
Director of the main host Laboratory	-
PhD Speciality	Mécaniques des sols
Axis of the performance contract	2 - COP2017 - More efficient and resilient infrastructure
Main location	Marne-la-Vallée
Doctoral affiliation	ECOLE CENTRALE NANTES
PhD school	Sciences de l'Ingénierie et des Systèmes (SIS)
Planned PhD supervisor	SEDRAN Thierry - -
Planned financing	cdd - Ifsttar
Abstract Soil liquefaction occurs when a saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress such as shaking during an earthquake or other sudden change in stress condition, in which material that is ordinarily a solid behaves like a liquid. To avoid liquefaction, soil densification is often used by various methods. The approach in this study will be based on the internal enhancement by bio-precipitation of calcium carbonates by bacteria. Bioprecipitation is a natural phenomenon that can involve prokaryotic microorganisms according to the following reaction: Ca2 + +2 HCO3- → CaCO3 + CO2 + H2O After determining the bioprecipitation conditions, the improvement of the mechanical properties of soils by bio-precipitation of calcium carbonates will be examined in this study by: 1) measurements of shear wave velocity (P -RAT) throughout the entire process and 2) by performing cyclic tests on improved and unimproved samples using a single device (TxSS)
Keywords :	Soil mechanics, liquefaction, bio-precipitation, Soil consolidation

List of topics

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