This is the 26th edition of the GéoMécanique newsletter. This new edition contains the latest news regarding research publications, conference visits and other activities of the staff and students from the GéoMécanique group of Laboratoire 3SR (Sols, Solides, Structures – Risques). If you have something you want to share, please don’t hesitate to contact us at: firstname.lastname@example.org . Please feel free to forward the letter to colleagues and friends, and let them know that they can subscribe by themselves here.
Honors and Awards
Bruno Chareyre and his team of Yade-MPI hackers participated in, and won, the Hackathon for High Performance Computing (HPC) 2018 organized by GENCI . As highlighted here , 11 teams comprised of 70 total participants competed to optimize high performance scientific codes ranging from fluid Mechanics to bioinformatics. 3SR’s Yade-MPI Discrete Element Method (DEM) team was comprised of 6 PhD students and Post Docs [*] who gathered for 2 full days and 19828 core hours of dense hacking. At the end, our Grenoble based DEM team managed to exceed objectives by 300% by profiling the code, incorporating efficient MPI communications, and adding user friendly Yade GRICAD utilities. For more information, watch the GRICAD video  .
[*]Robert Caulk, William Chèvremont, Deepak Kunhappan, Jean Pourroy, François Kneib, Thomas Guntz
Visits and conferences
Eddy and Cino attended the Patterns in Geomechanics workshop (PIG 2019) in Sydney, Australia (https://www.benjymarks.com/patterns-in-geomechanics-2019/). They gave two talks on “Experimental observations of emergence of shear bands at different scales” and “Localized compaction in Tuffeau de Maastricht”, respectively.
Cino spent the whole month of February 2019 as a visiting professor at the University of Sydney, with Itai Einav and his group of the Particles and grains laboratory (https://sydney.edu.au/engineering/our-research/laboratories-and-facilities/scigem.html). While in Australia, Cino also visited colleagues at the University of Newcastle (https://www.newcastle.edu.au/profile/olivier-buzzi), the Australian National University in Canberra (https://physics.anu.edu.au/appmaths/people/profile.php?ID=720&tab=current_projects), and Monash University in Melbourne (https://www.monash.edu/engineering/hahbui)
Maddi Etxegarai defended her thesis on January 21. Her PhD is entitled “Coupled hydro-mechanics of reservoir rocks studied by quantitative in-situ neutron imaging”, and was supervised by Erika Tudisco and Steve Hall at Lund University, Sweden, and Alessandro Tengattini and Cino Viggiani at 3SR.
In January 2019, Thanos Papazoglou has started a 10-month post-doc at 3SR. He will be working at the ANR project STOWENG (underground STOrage of reneWable ENergies
in low permeability Geomaterials), lead by Giulio Sciarra in Nantes.
On February 2019, Alessandro Tengattini has started a new (non permanent) position of “Joint UGA-ILL Research Scientist”. The “joint” means that his time (and salary) will be shared by UGA and ILL.
Katia Boschi is visiting us for two months in the framework of a collaboration with Prof. Claudio Giulio di Prisco at Politecnico di Milano. Katia is starting a PhD on numerical and analytical modeling of grout injection in granular materials, as part of a larger research project in Milano with industrial partner BASF. Indeed, grouting and jet-grouting are geotechnical consolidation techniques commonly employed to improve the mechanical behavior of soils. Although these techniques are common, the micro-mechanical processes taking place at the local level are not yet quantitatively and qualitatively understood and hence rightly modeled. This first stay in Grenoble aims at setting up preliminary models with the hydromechanical couplings available in Yade-DEM, under the guidance of Bruno Chareyre.
The paper “Quantitative prediction of discrete element models on complex
loading paths” by Luc Sibille, Pascal Villard, Félix Darve and Rodaina
Aboul Hosn is now published online to be included in the next special
issue “Particle Methods in Geomechanics” of IJNAMG. https://onlinelibrary.wiley.com/doi/10.1002/nag.2911
Recent results on the geogrid modeling in the Discrete Element Method framework are shown in the video of this newsletter. The discrete geogrid modeling was implemented in the YADE code using the cylinders and particle facets described respectively in the works of Bourrier, Kneib, Chareyre et al. (2013) and Effeindzourou, Chareyre, Thoeni et al. (2016). At the end of the video, there is a geogrid pull-out simulation using spheres as granular material. Results are obtained by Marcus Guadagnin Moravia.