Grenoble Geomechanics

As your evening commute begins to lighten up* with the approach of Spring, so does the productivity in our GéoMéchanique group at Laboratoire 3SR (Sols, Solides, Structures – Risques). Within the 30th edition of our newsletter, you can pick the greenest pre-Spring GéoMéchanique buds including seminar presentations, workshops, and publications. Please forward this letter to colleagues and friends. Enjoy!

*note we make no mention here of your commute “drying up”

If you have something you want to share in the next newsletter, please do not hesitate to contact us at: geomecanique.newsletter@3sr-grenoble.fr .

3SR seminar series in full swing

• January 16, 2020: Robert Caulk (3SR) gave a talk on “A pore-scale Thermo-Hydro-Mechanical coupled model for particulate systems”
• January 23, 2020: Ryan Hurley (Johns Hopkins, USA) gave a talk on “Experimental Micromechanics of Geologic Materials with X-ray Diffraction and Tomography”
• 
• January 31, 2020: Ioannis Stefanou (Ecole Centrale Nantes) gave a talk on “Controlling Anthropogenic and Natural Seismicity: Insights From Active Stabilization of the Spring‐Slider Model”

Don’t miss it! Takashi Matsushima on March 10th at14h00 discussing “Recent progress in granular statistical mechanics”.

For a full list of past and planned seminars, head over to the brand new 3SR website.

Granular GéoMéchanique ambassadors!

A (very nice!) three-day workshop on Emerging Scales in Granular Media took place in Hong Kong (14-16 Jan 2020)

Among roughly forty invited speakers, Cino and Felix represented 3SR:

GéoMéchanique team seminar activity

Thanks to our new seminar organizer, Ankit Sharma, our team continues to meet regularly to exchange ideas about ongoing research. On December 5th, we heard from Agathe Furet on her concrete impact research and Ritesh Gupta (pictured below) on the behavior of structural piles under combined cyclic loading. On January 16th, Maria Delli Carpini introduced us to her work modeling geosynthetics in cohesive soils with the discrete element method.

Don’t miss it! Coming up on February 13th at 12h30, we have Cino Viggiani presenting some recent observations on the formation of ice lenses in clays.

Recent Publications

• Accelerating yade’s poromechanical coupling with matrix factorization reuse, parallel task management, and gpu computing. by Robert Caulk, Emanuele Catalano, and Bruno Chareyre, in Computer Physics Communications 248 (2020): 106991.
• An original approach of boundary conditions on model granular solids has been implemented in Yade-dem, a presentation of the method and an application are presented by Gerald Pekmezi, David Littlefield, and Bruno Chareyre, in Statistical distributions of the elastic moduli of particle aggregates at the mesoscale,  Int. J. Impact Engineering (139), 2020.

Familiar faces back to haunt 3SR

Welcome Marta Stasiak back for her new one year post-doc concerning “L’étude numérique du comportement mécanique de blocs quasi-fragiles” under supervison of Gaël Combe and Vincent Richefeu.

Elin Törnquist, a PhD student from Lund University in Sweden, returns to complete a second three month residency here at 3SR where she will perform neutron and XRay imaging at the ILL in collaboration with Alessandro Tengattini and Edward Ando.

Geomaterials short course (still) offered – June 2020!

Registration is now open for our very own workshop entitled “Mechanics of geomaterials: from micro to macro”, which will take place in Grenoble on June 29-30 2020. The workshop is in the framework of the IACMAG conference. Download the flyer for more information.

The school year has started and that means autumn is threatening your shorts, swim trunks, and sandals. But not to worry, unlike the now barren fig tree out front Galilée, the 28th edition of the GéoMécanique newsletter brings fruit in the form of summer 2019 publications, conferences, invited talks, and activities generated by the GéoMécanique group at Laboiratoire 3SR (Sols, Solides, Structures – Risques). Please feel free to forward this letter to colleagues and friends. Enjoy!

If you have something you want to share in the next newsletter, please don’t hesitate to contact us at: geomecanique.newsletter@3sr-grenoble.fr .

Don’t forget your roots (for slope stability considerations)!

Glyn Bengough (University of Dundee and Hutton Institute) visited us on September 17th, 2019 to give the first seminar of our annual 3SR seminar series. His engaging seminar covered “Root–soil mechanical and hydrological interactions different scales”.

Glyn enlightening 3SR on root-soil mechanical interactions

DEM8 conference recap

A group of researchers and students represented 3SR at DEM8, the 8th international conference on discrete element methods at University of Twente in Enschede, Netherlands. Between July 22-26th, Vincent Richefeu chaired the particle breakage session, Bruno Chareyre presented in the open source software and two phase flow sessions [1][2], Cyrille-B Couture discussed FEM-DEM couplings, and Robert Caulk introduced an open framework for thermo-hydro-mechanical simulations [3].

[1] Chareyre B., Montellà, E.P., Yuan, C., Gens, A. (2019), A hybrid pore network – LBM method for integrating flow of immiscible phases in DEM. In 8th International Conference on Discrete Element Methods. (fulltext)

[2] Caulk, R.A., Kozicki, J., Kunhappan, D., Maurin, R., Montellà, E.P., Sweijen, T., Yuan, C., Chareyre, B. (2019), Yade’s (undeniable) transformation into a model project of optimzation, multi-physics couplings, and user support. In 8th International Conference on Discrete Element Methods. (fulltext)

[3] Caulk, R.A., Chareyre, B. (2019), An open framework for the simulation of coupled Thermo-Hydro-Mechanical processes in Discrete Element Systems. In 8th International Conference on Discrete Element Methods. (fulltext)

Up and Running! Open Geomechanics Journal 

Cino Viggiani and Edward Andò (among the editors of Open Geomechancics) are pleased to announce that Open Geomechanics, a diamond open access journal run by researchers, is up and running. There are already two papers available online (open access of course); one demonstrating a hyperplasticity framework conveyed with convex analysis [1] and the other mathematically examining the effect of proppant on hydraulic fracture geometry [2]. Find both articles along with their riveting review histories online. Consider adding your next article to this diamond open access journal.

[1] Houlsby, Guy T. Frictional Plasticity in a Convex Analytical Setting. Open Geomechanics, Volume 1 (2019) article no. 3, 10 p. doi : 10.5802/ogeo.2. (full text)

[2] Selvadurai, A.P.S. Proppant-Induced Opening of Hydraulically Created Fractures. Open Geomechanics, Volume 1 (2019) article no. 2, 10 p. doi : 10.5802/ogeo.1. (full text)

A look at some recent journal publications

Max, Eddy, and Cino coauthored the following two papers which were accepted for publication:

Nadimi S., Fonseca J., Andò E., Viggiani G. (2019) – A micro finite element model for soil behaviour: experimental evaluation for sand under triaxial compression. Géotechnique , accepted August 2019.

Wiebicke M., Andò E., Viggiani G., Herle I. (2019) – Measuring the evolution of contact fabric in shear bands with x-ray tomography. Acta Geotechnica, accepted September 2019.

PhD graduates!

On September 13, Ilaria Soriano successfully defended her PhD in Edinburgh, Scotland. Ilaria’s PhD is entitled “Bands of localised deformation in weakly cemented sands: the example of Bédoin (southern France)” and was jointly supervised by Elma Charalampidou and Helen Lewis at Heriot-Watt University and Cino Viggiani at Université Grenoble Alpes. This was a PhD in cotutelle, i.e., she obtained a PhD from both universities.

On July 16th, Eduard Puig Montellà presented his research encompassing “Modeling capillarity and two-phase flow in granular media: from pore-scale to network scale”. He was supervised by Bruno Chareyre and Antonio Gens, while his jury included: Hugues BODIGUEL (INP Grenoble), S. Majid HASSANIZADEH (Utrecht University), Jean-Yves DELENNE (INRA), Vanessa MAGNANIMO (University of Twente).

Recommence – Masters Program 

On September 9, the 13th edition of our well-received one-year master program in “geomechanics, civil engineering and risks” recommenced in Grenoble. This year, we have a diverse class of 24 students coming from 11 countries worldwide.

Lectures and talks 

Cino Viggiani was busy this summer delivering four keynote/plenary/invited lectures on opposites sides of the globe:

– June 2019: plenary lecture at the annual conference of the Engineering Mechanics Institut (EMI2019) in Pasadena, USA (conference link)

– June 2019: keynote lecture at the 7th International Symposium on Deformation Characteristics of Geomaterials (IS-Glasgow) in Scotland  (conference link)

– September 2019: invited plenary lecture at the 17th European Conference on Soil Mechanics and Geotechnical Engineering (ECSMGE) in Reykjavik, Iceland (https://www.ecsmge-2019.com/). A pdf of the associated paper can be found here.

– September 2019: invited lecture at the conference of AIMETA, the Italian Association of Theoretical and Applied Mechanics (conference link)

Cino Viggiani in between the two organizers of IS-Glasgow –: Erdin Ibraim (left) and Alessandro Tarantino (right).

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: geomecanique.newsletter@3sr-grenoble.fr . 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 [1]. As highlighted here [2], 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 [3] .

[1] http://www.genci.fr/fr

[2] https://hackathon-hpc.sciencesconf.org/resource/page/id/6

[3] https://gricad.univ-grenoble-alpes.fr/video/hackathon-genci-2018-grenoble

[*]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)

People

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.

Seizo Tanaka and Kyosuke Yamamoto both from the University of Tsukuba presented their work on fluid-structure interaction and bridge vibration to the lab at the beginning of March.

Publications

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

Miscellaneous

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.

This is the 25th 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: geomecanique.newsletter@3sr-grenoble.fr . Please feel free to forward the letter to colleagues and friends, and let them know that they can subscribe by themselves here. By the way, we wish you a merry Christmas and a happy new year!

Visits and conferences

The ALERT Olek Zienkiewicz Winterschool 2018 on “Natural versus compacted clayey soils: from micro to macro behaviour and modelling” was held in Bari (Italy) from November 5 to November 9. Several (current or former) students from our team attended the school: Angela Casarella, Liliana Gramegna, Mathias Tolomeo, and Alessandro Fraccica (see photo group below). Cino Viggiani gave a lecture on “Experimental characterization of localized deformation in clays and clay rocks”.

On December 11, a half-day workshop in honor of our colleague Félix Darve took place in Grenoble. Four talks were given by:

• Eduardo Alonso (Universidad Politécnica de Cataluña, Spain): Coarse granular soils. Long term behaviour.
• Claudio di Prisco (Politecnico di Milano, Italy): Extension of controllability theory to viscoplastic constitutive relationships.
• Patrick Selvadurai (McGill University, Canada): Dilatancy and Rupture of Elastically Constrained Geological Interfaces.
• Manuel Pastor (Universidad Politécnica de Madrid, Spain): Modeling of two-phase landslides.

The day was closed by Félix Darve, who gave a talk entitled “Félix in Geomechanics Wonderland”.

People

Mathias Tolomeo defended his thesis on October 20. His PhD is entitled “Forces inferred from macroscopic loading and grain motions”, and was supervised by Vincent Richefeu, Gaël Combe, Cino Viggiani, and Jean-Noël Roux.

Thanos Papazoglou defended his thesis on December 13. His PhD is entitled “An experimental study of localized compaction in high porosity rocks: the example of Tuffeau de Maastricht”, and was supervised by Cino Viggiani, Christophe Dano, and Giuseppe Buscarnera (Northwestern University, USA).

We had a visit from Yorgos Birmpilis from Chalmers University in Gothenburg (Sweden) with his beautiful x-ray compatible Bishop & Wesley triaxial for soft clays… 74 tomographies per test!

Marius Milatz from the Technical University of Hamburg came with his RaspberryPi powered loading system to compress unsaturated columns of sand and following granular rearrangements and water movement with x-ray tomography.

Publications

The paper entitled “Field experiments at three sites to investigate the effects of age on steel piles driven in sand” by Roselyn Carroll & P Carotenuto (NGI), C Dano, & I Salama (3SR), M. Silva (Universidad Técnica Federico Santa María), K Gavin (TU Delft) and R Jardine (Imperial College London) has been accepted for publication in Geotechnique.

Miscellaneous

On December 4, the sculpture “Essere vento, 2015″ was officially presented in our lab, in the presence of the director of the Museum of Grenoble, the president of UGA, a city council representative, and — most importantly — almost all the members of 3SR. “Essere vento” has been sculpted by the artist Giuseppe Penone and it is the result of a 4-year collaboration between him, Joël Chevrier, Eddy Andò and Cino Viggiani.

In this Christmas edition, the PhD student Ritesh Gupta presents two videos showing the simulated response of a model monopile installed in calibration chamber under the action of combined vertical, horizontal and moment (VHM) loading. The simulation is performed using PlAXIS 3D, comprising of following 4 Steps:

Initial phase: Geometry and material definition
Phase 1: Vertical and lateral confining pressure application
Phase 2: Pile installation
Phase 3: Axial loading application
Phase 4: Lateral loading application

The objective here is to find out the zone of influence in sand volume under the combined loading action in the installed pile. It will aid in decision-making for the strategic location of soil stress transducers in the experimental sand volume. Moreover, the application of lateral load till failure provides a rough estimate of the static load capacity of model pile and subsequently determines the amplitude of cyclic loading.

This is the 24th 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: geomecanique.newsletter@3sr-grenoble.fr . Please feel free to forward the letter to colleagues and friends, and let them know that they can subscribe by themselves here. Enjoy

Visits and conferences

Ivan Deiros has participated in the Fourth International Conference on Railway Technology, Sitges, Spain, on September 3-7. He gave a talk on ”Modelling ballast wear: From DEM simulations to shearing at the contact scale“

Some members of 3SR attended the IS-B2G Symposia Atlanta 2018 on September 10-13, 2018. Our group gave the following talks:

• “Local macro-element model of rigid monopiles in sand” was presented by Ritesh Gupta

• Gael Combe presented the work of Jeanne Doreau-Malioche entitled: “Grain- scale study of pile installation and subsequent axial loading cycles”.

• Cino Viggiani gave a keynote lecture entitled: “Advances in 3D experimental geomechanics at the grain scale: can we measure fabrics?”

• Floriana Anselmucci presented her work entitled: ” Quantifying micro-structural changes in sand due to plant root growth”.

Cino after an exhausting session in Atlanta

The ALERT Geomaterials Workshop 2018 was organized from the 1st to 3rd of October in Aussois, France. The following presentations were given by members of our team:

• “Neutron and x-ray imaging for capturing flow phenomena in geomaterials” by Alessando Tengattini.

• “Shear behaviour of carbonate rock/grout interfaces: application on offshore piles of wind turbines” by Eleni Stavropoulou.

Plus, some posters were presented:

• “Why does geomechanics need tube-shaped grains? DEM insight into grain crushing”, Marta Stasiak

• “Tensile and compressive failure of micro-concrete: from mechanical tests to FE meso-model with the help of x-ray tomography”, Olga Stamati

• “Multiscale model of partially saturated media based on a pore-network approach and lattice Boltzmann method”, Eduard Puig Montellà.

• “Characterization of Diffuse and Localized Deformation in a Porous Sandstone: A True-Triaxial Experimental Study”, Cyrille Couture.

• “Local macro-element model of rigid monopiles in sand”, Ritesh Gupta.

• “NeXT-Grenoble: The Neutron and X-ray Tomograph in Grenoble”, Alessando Tengattini.

People

Angela Casarella started her PhD on “Effect of varying temperature and degree of saturation on soils THM behaviour: application to energy geostructures ”, under the supervision of Alice Di Donna and Benjamin Loret.

Christos Papazoglou started his PhD in the team the 1st October. The title of the PhD is “A micromechanical study of the chemo-hydro-mechanical behavior of granular cemented materials”. He will be supervised by Alessandro Tengattini, Nicolas Lenoir and Cino Viggiani.

Floriana Anselmucci moved on the other side of the Atlantic and she will spend 6 months in GeorgiaTech to work with her co-advisor Chloé Arson.

Dorjan Dauti has defended on September 26. His PhD entitled “A 3D hydro-mechanical discrete element model for hydraulic fracturing in naturally fractured rock”, supervised by Stefano Dal Pont,
Benedikt Weber and Matthieu Briffaut.

Jeanne Doreau defended her thesis the 28th of September. Her PhD is entitled “Grain-scale investigation of sand-pile interface under axial loading conditions using x-ray tomography”, supervised by Gaël Combe and Cino Viggiani.

Jelke Dijkstra is visiting us from Chalmers University for three weeks between October and November.

Miscellaneous

Maria Delli Carpini sent us a nice video from her PhD that we want to share with you. Here there’s a brief description of her research:

Ground subsidence represents a significant and complex problem. Localized loss of ground support could be the cause of the collapse of the infrastructure. The geosynthetic reinforcement (GR) is an economic and effective solution to avoid this hazard. It can reduce the total and differential settlement problems. When the geosynthetic sheet is applied on the cohesive soil, it takes up the vertical loads and diffuses them in the form of tensile forces transferred by friction in the anchorage areas.

The developed numerical model enables to analyze the mechanism of the transfer of the load into a cohesive soil and the deformations into the geosynthetic sheet as well. The results are compared with experiments that have been previously conducted on a small scale model.

This is the 23rd edition of the GéoMécanique newsletter. After the summer break we are ready to begin the new academic year full of energy and fresh ideas! 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: geomecanique.newsletter@3sr-grenoble.fr . Please feel free to forward the letter to colleagues and friends, and let them know that they can subscribe by themselves here. Enjoy

People

Two members of the team are involved in a newly launched non-profit Open Access geomechanics journal entitled “Open Geomechanics”. You can check the website here: http://www.opengeomechanics.org

It aims for quality and not quantity of papers, and is now open for submissions! If you’re wondering why Cino resigned from the editorial panel of Acta Geotechnica, now you know…

Prof.r Gudmund Reidar EIKSUND has joined the Geomechanics Team for 1-year sabbatical period at 3SR. Gudmund is Professor at NTNU in Norway and his main research topics deal with offshore foundations (including for offshore wind turbines), from practical and numerical points of view. Welcome Gudmund !

PhD students Marcus Guadagnin and Eduard Puig left Grenoble to continue their research in Brazil and Barcelona, respectively, but don’t panic, Eduard will come back to the lab to see you and present the PhD defense.

Honors and Awards

Dorjan Dauti (thesis Tec21, supervised by S.Dal Pont) received the 3rd price award in the competition “Young Researcher” (prix Jeunes Chercheurs “Rene Huopert”) given by AUGC (Association Universitaire de Génie Civil).

Visits and conferences

Cino went to Hong Kong where he sat in the committee for the PhD defense of Xingyue Li (photo 1) and Huanran Wan (photo 2), both supervised by Jidong Zhao of the Hong Kong University of Science and Technology. He also gave a talk at HKUST and met the current president of ISSMGE, Charles Ng (photo 3)

Photo 2: PhD defense of Huanran Wan

Photo 1: PhD defense of Xingyue Li

Photo 3: Cino and Charles Ng

In August, Cino gave a keynote lecture at the 41st Solid Mechanics Conference in Warsaw, Poland. He will also give a keynote lecture at IS-Atlanta 2018, to be held in September 2018.

Dorjan Dauti and Stefano Dal Pont attended the 36^èmesRencontres Universitaire de Génie Civil from 20-22 June 2018 in Saint-Etienne where Dorjan presented the conference paper entitled “In-situ Neutron tomography and 3D numerical modeling of moisture distribution in concrete at high temperature“.

Dorjan Dauti attended and presented in the 6th European Conference on Computational Mechanics (ECCM) jointly organized in Glasgow with the 7th European Conference in Fluid Dynamics (ECFD) from 11-15 June 2018. The title of the presented work, coauthored by Stefano Dal Pont, Benedikt Weber and Matthieu Briffaut, was: Investigation of constitutive laws for modelling concrete at high temperature by the aid of neutron imaging.

Alessandro Tengattini and Maddi Etxegarai went to Australia to attend the11th World Conference on Neutron Radiography from 2 to 7 September 2018. Alessandro gave a talk entitled “Recent developments from NeXT-Grenoble, the Neutron and X-ray Tomograph in Grenoble” while Maddi presented the following work: “Investigation of hydromechanical processes in porous rock using 4D neutron imaging”.

Publications

The paper “Analysis of moisture migration in concrete at high temperature through in-situ neutron tomography” by Dorjan Dauti, Alessandro Tengattini, Stefano Dal Pont, Nikolaj Toropovs, Matthieu Briffaut and Benedikt Weber has been published in Cement and Concrete Research (https://www.sciencedirect.com/science/article/pii/S0008884618301613).

The paper “How does strain localise in standard triaxial tests on sand: revisiting the mechanism 20 years on” – by Jacques Desrues, Eddy Andò, Federica Mevoli, Laurent Debove and Cino Viggiani – has been published in the journal “Mechanics Research Communications”.

The article “Open-source support toward validating and falsifying discrete mechanics models using synthetic granular materials—Part I: Experimental tests with particles manufactured by a 3D printer.” by Ritesh Gupta, Simon Salager, Kun Wang and Waiching Sun was published in Acta Geotechnica in July 2018.

Miscellaneous

Voussoir Monobloc Compressible (VMC) is an innovative technology of precasted concrete tunnel linings integrating a layer composed of tube-shaped grains such that its compressible behavior is activated (Andra’s & CMC patent). Research study carried out in 3SR by M. Stasiak, G. Combe, V. Richefeu, P. Villard and J. Desrues concerns mechanical behavior of this brittle granular material paying special attention to grain crushing. DEM simulation of oedometer test shows high compressibility of material and progressive grains fragmentation (see the video below).

This is the 22nd edition of the GéoMécanique newsletter. The month of May and the days off are over. Despite the holidays, our group doesn’t rest and keeps working hard! 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: geomecanique.newsletter@3sr-grenoble.fr. Please feel free to forward the letter to colleagues and friends, and let them know that they can subscribe by themselves here. Enjoy.

A couple of weeks ago the “Journées du labo” took place in Avigliana. We want to thank Olga , Dominique, Mireille and Cyrille for organizing this event. We had the chance to socialize with our colleagues during the coffee breaks, copious lunches and social activities. Plus, some people of our group presented their research to the whole lab. However, the most significant achievement was carried out by Marcus Guadagnin Moravia and Bruna Garcia, the video contest winners and members of the GéoMécanique group:

Publications

The article “Liquid water uptake in unconfined Callovo Oxfordian clay-rock studied with neutron and X-ray imaging” by Eleni Stavropoulou, Edward Andò, Alessandro Tengattini, Matthieu Briffaut, Frédéric Dufour, Duncan Atkins, Gilles Armand, has been published in Acta Geotechnica

“A discrete numerical model involving partial fluid-solid coupling to describe suffusion effects in soils” by R.Aboul Hosna, L.Sibille, N.Benahmed and B.Chareyre has been published in Computers and Geotechnics.

The article “Phase segmentation of concrete x-ray tomographic images at meso-scale: Validation with neutron tomography” by Olga Stamati, Emmanuel Roubin, Edward Andò and Yann Malecot, has been published in Cement and Concrete Composites.

“Modeling concrete exposed to high temperature: Impact of dehydration and retention curves on moisture migration” by D. Dauti, S. Dal Pont, B. Weber, M.Briffaut, N. Toropovs, M. Wyrzykowski, G. Sciumé, has been published in the International Journal for Numerical and Analytical Methods in Geomechanics

“Critical review of the description of concrete’s damage-permeability coupling using continuous and regularized elastic-based damage models – New strain-based matching law” by D. Bouhjiti, M. Ezzedine El Dandachy, F. Dufour, S. Dal Pont, M. Briffaut, J. Baroth, B. Masson has been accepted in the Numerical Methods in Geomechanics.

“COST TU1404 benchmark on macroscopic modelling of concrete and concrete structures at early age: Proof-of-concept stage” by A. Jędrzejewska, F.Benboudjema, L. Lacarriere, M. Azenha, D. Schlicke, S. Dal Pont., A. Delaplace, J. Granja, K. Hájková, P. Heinrich, G. Sciumè, E. Strieder, E. Stierschneider, V. Smilauer, V. Troyan, has been published in Construction and Building Materials.

The International Society of Porous Media “Interpore” released a Research Spotlight on Yade-DEM.org, and more specifically the hydro-mechanical couplings available therein.

Visits and conferences

Bruno Chareyre gave a keynote lecture (Coupling DEM and fuids at the pore scale: recent advances and further issues) at the 2nd Yet Another Discrete Element Workshop. The workshop was organized at Irstea Aix en Provence. Eduard Puig also participated with a regular talk entitled “Micromechanical study of multiphase flow based on the lattice Boltzmann method”

Mustafa Sari from the University of New South Wales visited the lab in May and gave a talk on “Geomechanical Modelling of Pore Collapsing in Soft Porous Rocks: Insights From Triaxial Experiments and Numerical Simulations in Sandstone, Mudstone And Shale Samples”.

The International Symposium on Micro to macro mathematical modelling in soil mechanics was held in Reggio Calabria (Italy) on May 29 – June 01, 2018, at the University Mediterranea of Reggio Calabria. Our group delivered the following talks:

• “Experimental access to the mechanics of sand at its constitutive scale”, Edward Andò
• “Measuring the evolution of contact fabric in shear bands with x-ray tomography”, Max Wiebicke
• “An assessment of discrete element approaches to infer intergranular forces from experiments on 2D granular media”, Mathias Tolomeo
• “In-situ x-ray tests for an image-based FE meso-model for cementitious materials”, Olga Stamati
• “Discrete element modeling of crushable tube-shaped particles”, Gaël Combe
• “A micro-mechanics focused experimental investigation of cemented granular materials”, Alessandro Tengattini.

Bruno Chareyre attended and presented in the InterPore 10th Annual Meeting and Jubilee which took place in New Orleans from May 14th-17th, 2018.

Group photo of Micro to macro Mathematical Modelling in Soil Mechanics conferece

People

Ivan Deiros has defended the 2nd of May, 2018. His PhD entitled “A Multi-scale study of the degradation of railway ballast” was supervised by Gaël Combe, Fabrice Emeriault, Charles Voivret and Jean-François Ferellec.

Robert Caulk, PhD student at University of California San Diego, has been selected as a recipient of a Chateaubriand Fellowship supported by the Make Our Planet Great Again Initiative. Robert is a developer and active member of the Yade-dem.org community. This grant will cover a 9-month stay in Grenoble for further collaborative efforts in relation to micro-hydro-mechanical couplings.