Séminaire

Journée Géomécanique en l'honneur de Félix Darve

Séminaire, Cérémonie Le 11 décembre 2018

Amphi Kilian

Patrick Selvadurai (Canada), Eduardo Alonso (Espagne), Manolo Pastor (Espagne) et Claudio di Prisco (Italie).

Jacky Mazars et Félix Darve comptent parmi les plus importants contributeurs dans le domaine des sciences du génie civil et de la mécanique des solides. En l'honneur de leurs carrières (solides et non linéaires !), leurs collègues du laboratoire 3SR ont invité collègues et amis pour leur rendre hommage lors d'une conférence en deux sessions, l'une dédiée à la géomécanique, l'autre aux risques et à la vulnérabilité des ouvrages du génie civil. Tous deux devraient apprécier grandement ce bien beau cadeau jute avant Noël !

Programme du workshop (PDF, 690.35 Ko)

Jacky Mazars et Félix Darve

Fabio Gabrieli and Antonio Pol

Séminaire Le 15 novembre 2018

14h00

Bâtiment Galilée, salle 011

Fabio Gabrieli (assistant professor) and Antonio Pol (PhD student) from the University of Padova, (ICEA dept.) are visiting us for a couple of days mid November.

DEM modelling of cortical meshes

Cortical meshes are widely used in mountainous areas to protect settlements and infrastructure from the risk of damages and serviceability losses.  At the moment, their design is almost empirically-based because of the complexity of their mechanical behaviour and the difficulties in modelling the rock and soilbackfill. Moreover, laboratory tests are often not representative of the real in-situ conditions.

ew numerical models are able to capture the mechanical behaviour of these meshes at different scales as the discrete element method. The power of this method lies in the possibility to investigate large deformations, local ruptures, dynamic problems and also to appreciate details of the soil-mesh interaction as well as the effect of the particle size.

Steel elements of the mesh can be discretized by means of remote interactions or cylindrical elements having the same tensile properties as that of the wires. The Soil or rocks behind are modelled with spheres or clump of spheres.

Using a particle-based model, several important information for the design and optimization of these meshes can be obtained in terms of mechanical performance from laboratory to field scale.

Mesh

Robert Caulk

Séminaire Le 8 novembre 2018

14h00

Bâtiment Galilée, salle 011

Robert has a M.Sc in Civil Engineering from the University of Vermont where he worked as a NASA fellow evaluating key geomechanical aspects of deep and shallow geothermal energy. He is now working as a Chateaubriand Fellow at Laboratoire 3SR where he is focused on using the Discrete Element Method (DEM) to gain insights into the rock mechanics associated with coupled thermal-hydraulic-mechanical processes.

Micromechanical modeling of acoustic emissions in heterogeneous rocks during tensile fracture

The presentation will cover a micromechanical investigation of acoustic emissions (AE) in heterogeneous rocks. First, the heterogeneity of a sandstone rock is statistically quantified using cathodoluminescent image analysis of interacting grains. Next, the statistical description of heterogeneity is used to augment the micromechanical contact model in Yade DEM. The heterogeneity model is then validated by modeling AE as a strain energy change based process in Yade. We validate the combined heterogeneity and AE models using experimental three point bending tests. Further validation is performed by collecting DEM wave propagation associated with broken bonds. Traditional arrival time based source localization is performed and compared to strain energy based AE locations. We conclude that the stochastically augmented DEM model can accurately model the spatial and temporal development of AE during tensile fracture of heterogeneous rock, but the process of statistically quantifying rock heterogeneity may be limited to single scale heterogeneity descriptions of sedimentary rock types.

Robert Caulk

Pr. Patrick Paultre

Séminaire Le 22 octobre 2018

10h00

 Amphi Kilian, 1381 Rue de la piscine

Dans le cadre des séminaires RISK, le Professeur Patrick Paultre de l'Université de Sherbrooke (Canada), titulaire de la Chaire Canadienne en Ingénierie Sismique, lauréat du Prix Armand-Frappier 2015, donnera un séminaire sur la résilience des acteurs locaux à Haïti après le tremblement de terre de 2010. Pr. Paultre recevra par ailleurs dans quelques mois le Doctorat Honoris Causa de l'Université Grenoble Alpes.

10h : "From capacity design to resilience : a change of paradigm in light of the Haiti and New Zealand earthquakes"

A historical review of the evolution of seismic design codes is presented. It is shown that capacity design, which has been the accepted design philosophy for the last 50 years, has evolved from lessons learned after damaging earthquakes. However, recent damaging earthquakes in Haiti, Chile and New Zealand have proved that this approach is not viable, although still in use worldwide. Reconstruction of destroyed significant part of major cities has brought the concept of structure resilience. It is shown that a paradigm shift is needed. Different techniques to increase resilience of cities are discussed.

11h  : "Hybrid testing for seismic characterization of members and structures"

Tests of structures and members have been the main support for development of analytical methods for the nonlinear study of structures under earthquake excitation. Due to laboratory limitations, most tests have been carried out on reduced size specimens and rarely on complete structures. Developments in control systems, software and testing apparatus have allowed the use of pseudo-dynamic tests of large scale members and structures as an alternative to reduced size shaking table tests. Advanced in software engineering and control systems allow today to perform hybrid dynamic, pseudo-dynamic and distributed tests. The presentations will illustrate different testing systems in use around the world and their application to important test programs.









 

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