Context and work environment
Description: Clay materials combine low permeability, high plasticity and strong sensitivity to moisture and temperature. They play a key role in the design of foundations, earth structures, energy geostructures, energy storage systems and engineered barriers (e.g. underground waste storage), being subjected to thermo-mechanical loading. Their behaviour emerges from coupled processes across multiple scales, ranging from molecular interactions between particles to macroscopic mechanical response. Among clay minerals, smectites are the most challenging to model. Their typical swelling behaviour originates from the interplay between interlayer water, ions and charged surfaces. Thermal loading induces counter-intuitive, non-monotonic changes in swelling pressure that existing mesoscale models fail to capture.
The objective of this PhD is to understand how hydration-state transitions in smectite clays, driven by water and ions confined at the nanoscale, control the swelling pressure response under thermal and mechanical loading, including its non-monotonic temperature dependence observed experimentally. By coupling all-atom molecular simulations, DLVO calculations and coarse-grained molecular dynamics, the PhD will bridge molecular-scale mechanisms and macroscopic behaviour. The transferability of the results to other interface-driven geomaterials, such as unsaturated soils, salt rocks and cementitious materials, will be evaluated.
Team description: The PhD will take place within two Tec21 labs on the Grenoble Campus:
- 3SR Laboratory (Soils, Solids, Structures, Risks), which has expertise in solid mechanics, multiscale modelling from the nano- to the macro-scale, and the thermo-hydro-mechanical behaviour of geomaterials.
- LIPhy (Laboratoire Interdisciplinaire de Physique), which has expertise in soft matter, statistical physics, and molecular simulation of nanoconfined fluids.
The PhD will be supervised by Alice Di Donna (3SR, thermo-mechanical behaviour and micromechanics of clays), Majdouline Laanaiya (3SR, molecular and coarse-grained simulations of geomaterials) and Simon Gravelle (LIPhy, molecular simulations of nanoconfined fluids). This team combines complementary expertise from the molecular to the continuum scale.
This recruitment takes place within the PhD@Tec21 Programme, which is co-funded as part of the Marie Skłodowska-Curie COFUND actions under the grant agreement #101217261. The recruitment process follows a specific selection and evaluation procedure with particular eligibility criteria, all of which are detailed in the applicant guide available on PhD@Tec21 Website.
Mission and main activities
Multiscale modelling of swelling clays: from water and ions at the nanoscale to thermo-hydro-mechanical behaviour
Description of the project: This project aims to link the molecular-scale mechanisms governing hydration and swelling in smectite clays to their macroscopic thermo-hydro-mechanical (THM) response. The mesoscale (100 - 1000 nm), where collective particle behaviour emerges, remains poorly understood and only partially captured by existing models. The PhD will build on 3SR's hybrid DLVO/coarse-grained models of clays and extend them to sub-nanometric particle separations thanks to molecular simulations of hydrated particles.
Three research axes will be explored:
- Molecular forces (non-DLVO). Hybrid molecular dynamics and Monte Carlo simulations of water and ions confined in smectite nanopores will be performed over a range of temperatures. They will provide the relationships between temperature, hydration state and disjoining pressure.
- Continuum scale (DLVO). Based on the predicted nanoscale contact forces from axe 1, a dataset of DLVO-based energy-separation functions will be developed for the clay particles. The theory will include effects from temperature, dielectric properties and electrolyte concentration.
- Prediction of THM behaviour. Effective interaction potentials derived from axe 2 will be implemented in coarse-grained simulations of smectite particle assemblies. The assemblies will be subjected to mechanical and thermal loading paths, and the predictions (swelling pressure, volumetric strains, mesostructure evolution) will be compared with available experimental data.
Together, these axes will clarify which nanoscale mechanisms control swelling in clays, and how they propagate to the mesoscale and macroscopic response. Depending on the candidate's background and interests, the focus may be more on one or two of these axes, although all three are important for the project.
Supervisors: Alice Di Donna, Majdouline Laanaiya (3SR) and Simon Gravelle (LIPhy)
Research fields: Geomechanics, molecular and coarse-grained simulation, soft matter physics, multiscale modelling
Possible secondments (industrial or academic partners): University of Strathclyde, Glasgow, UK (Prof. Alessandro Tarantino, expert in clay microstructure and hydro-mechanical coupling)
Doctoral school: I-IMEP² (Engineering – Materials, Mechanics, Environment, Energy, Processes, Production).
Desired profile and expected skills
The candidate should hold a Master's degree (or equivalent) in Engineering, Physics or Applied Sciences with a background in one or more of the following fields:
- Geomechanics, mechanics of materials or civil engineering
- Soft matter, statistical physics or physical chemistry
- Computational materials science or numerical modelling
Disciplinary skills, experience: Experience in numerical simulations, ideally molecular or particle-based methods, will be considered an asset. Knowledge of at least one scientific programming language is recommended. Solid English speaking and writing skills are required for oral presentations at conferences and writing articles.
Personal skills: This PhD position requires the ability to work in an interdisciplinary research team, with autonomy on individual tasks and regular interaction between the two labs. The ability to report honestly on progress and difficulties, and to actively contribute to the research of adapted solutions is crucial. The candidate will be required to conduct simulations and data analysis with rigor. He/She should demonstrate scientific curiosity and perseverance in problem solving. Solid communication and reporting skills (oral and written) are essential.
Employment benefits and conditions
Université Grenoble Alpes (UGA) is offering a 36-month full-time work contract.
In line with the European Commission rules for Marie Skłodowska-Curie grant holders, the remuneration will consist of a gross monthly salary of 2,650 EUR. The estimated net salary to be perceived by the PhD fellow will be between 2,050 and 2,150 EUR.
Benefits include:
- Access to a high-quality work environment, including a personal computer, scientific equipment and access to library and shared lab facilities
- Access to high-level scientific and inter-sectoral training through 120 hours of doctoral courses and workshops
- Opportunity for 2-month secondments at an academic institution or industrial partner during the 2nd year of the PhD
- A vast choice of networking events and activities within the PhD@Tec21 Programme and through the international network of MSCA fellows
- Access to the UGA International Student Office, to assist the PhD fellows in searching for accommodation in Grenoble and support with administrative issues including visas, health, bank accounts, etc.
- Visa fees and registration to the UGA Doctoral School are covered by PhD@Tec21
- 45 days of paid holidays
- Sick leave
- Parental leave
General information
Contact for the questions related to the position: PhD@Tec21 Management Board:
guillaume.chambon@univ-grenoble-alpes.fr / amelie.bataille@univ-grenoble-alpes.fr
