As the famous Albert Einstein once said, ‘The important thing is not to stop questioning. Curiosity has its own reason for existing.’ This quote perfectly captures the spirit our Geomechanics Group has been in these two last months. Whether you’re a scientist, a researcher, or simply someone who is curious about the latest developments in Geomechanics, we’ve got you covered here. Find all the news in the 42nd edition of our newsletter. Please forward this letter to colleagues and friends. Enjoy!
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- Dr Akihiko KONDO, from Port and Airport Research Institute (PARI) in Japan is with us at 3SR for three months. He and Dr. Gaël Combe plan to conduct collaborative research to apply the mechano-luminescent grains technique developed in PARI into “1g2e”, a unique shear device for 2D granular assemblies in 3SR. In this single one experiment, both the localization phenomenon of the strain field and the instantaneous generation and disappearance of stress chains and their transitions, and consequently a detailed description of deformation and failure mechanisms in granular materials can be obtained.
- A group of researcher and PhD students from the University of Hamburg, by the names of Marius Milatz, Michail Komodromos and Dennis Heinrich visited us within the two first weeks of April. They mostly played with our computed tomography scanner while performing triaxial tests whose results will be used as input in numerical models. Marius Milatz used also a custom-built miniaturised direct shear apparatus to look inside the shear behaviour of unsaturated granular materials on the grain and pore scale.
- We have Laura Perrotta, from Scuola Superiore Meridionale in Italy here with us at 3SR, to perform in-situ XR micro-CT tests on Lightweight Cemented Soil and image analysis of the results. Laura is a PhD student in Mathematical and Physical Sciences for advanced Materials and Technologies. She will be here for 2 months, from March, 27 to May, 27.
- Over the program ECOS Norte Perou “NUMOTOS”, Dominique Daudon spent 2 weeks, by mid-march 2022, in Lima at the Pontifica Universidad Catolica del Peru (PUCP), with Prof Sandra Santa Cruz and Paola Ita, a PhD student, to participate to the first seismic testing of 2 Dry Stone Retaining Walls (DSRW) on a vibrating table of the PUCP civil engineering department. As no literature has been encountered on similar walls testing, experimental campaings were really expected with great impatience. Despite the limits of the campaign, the experimental results demonstrated the positive effect of reinforcing the walls with a larger number of through stones, and the capability of the Yade numerical model to anticipate the experimental results. This peruvian journey follows the one of last July 2022 with Florent Vieux Champagne (3SR-RV), where static tests of 9 DSRW were performed to evaluate the fragility curves of 3 reinforced walls, and to calibrate the Yade DEM numerical model. Paola Ita will join us in 3SR this summer.
- On March 14th, Gustavo Pinzon defended his PhD thesis titled “Experimental investigation of the effects of particle shape and friction on the mechanics of granular media”, under the supervision of Cino Viggiani, Edward Andò, and Alessandro Tengattini. The jury was made up of Prof. Farhang Radjai (Université de Montpellier, France), Prof. Jean Michel Pereira (École des Ponts ParisTech, France), Prof. Gaël Combe (Université Grenoble Alpes), Prof. Catherine O’Sullivan (Imperial College London, UK), Prof. Antonio Gens (Universitat Politècnica de Catalunya), and Prof. Stephen Hall (Lund University, Sweden).
- On March 22nd, Jiamin became a doctor of Grenoble Alpes University as she defended her thesis titled “Numerical analysis of the rigid inclusions soil reinforcement technique” under the supervision of Daniel DIAS and Orianne JENCK. The members of the jury were Anne PANTET (Université de Normandie – Le Havre), Emmanuel BOURGEOIS (Université Gustave Eiffel), Pascal VILLARD (Université Grenoble Alpes), Luc THOREL (Université Gustave Eiffel), and Bastien CHEVALIER (Université Clermont Auvergne).
- Later, on March 31st Ilija Vego defended his thesis “Multi-modal investigation of hygroscopic granular media at high relative humidity” under the supervision of Cino Viggiani, Alessandro Tengattini, and Edward Andò. The jury was comprised of Prof. Emilien Azéma (Université de Montpellier, France), Prof. José E. Andrade (California Institute of Technology, US), Prof. Karen E. Daniels (North Carolina State University, US), and Gaël Combe (Université Grenoble Alpes, France).
The laboratory 3SR has contributed to two recent articles:
- Mourlas C., Pardoen B., Bésuelle P., Large-scale failure prediction of clay-rock from small scale damage mechanisms of the rock medium using multiscale modelling, Int J. for Numerical and Analytical Methods in Geomechanics, vol. 47, n° 7, pp. 1254-1288, doi.org/10.1002/nag.3513.
- Couture C., Bésuelle P., 2023, Three-invariants model and bifurcation analysis of deformation bands for a sandstone subjected to true triaxial loading paths, Acta Geotechnica, doi.org/10.1007/s11440-023-01811-w
Warm congratulations go to Alessandro Tengattini who was awarded the ENSA Neutron Instrumentation and Innovation Award in recognition of his outstanding contributions to the devlopment of Neutron Imaging, in particular for building the NeXT-Grenoble instrument at the Laue-Langevin Institute (ILL) and improving its capabilities to the highest possible level.
Alessandro arrived at the ILL in 2015 as a postdoc when he started the construction of D50-Tomo, which later became NeXT-Grenoble. In 2018 he became Joint Scientist ILL/UGA before being awarded, in 2020, the Imaging for Mechanics Chaire at UGA/ILL, when he then became an Associate Professor at the University.