Consultation des offres

Thèse CIFRE: Seismic behavior of rockfill dams with a dry stone rip-rap: a mixed DEM-FEM modeling CDD

Contact

Eric VINCENS

69134 Lyon

France

eric.vincens@ec-lyon.fr

Descriptions

Date de début :
01/10/2020
Date de fin :
30/09/2023
Date limite pour postuler :
31/05/2020
Descriptif :

Supervisor: Pr. Eric VINCENS, Ecole Centrale de Lyon, France
Co-supervisor: Dr. Fabian DEDECKER, ITASCA SAS, Lyon, France


This PhD thesis is carried out within the framework of a CIFRE contract between the stake holder Electricité de France (EDF) and ITASCA SAS.


1. Background
Rockfill dams with a dry stone rip-rap are composed of a backfill with compacted decameter blocks which is protected with a rip-rap made of hand-placed stones (Figure 1). EDF operates approximately ten dams of this kind that were built in the early 20th century.

The batter is unusual with a very steep slope of 1/1. The mechanical behavior of such structure is not very well understood, however, past modeling using a fully DEM approach showed that the rip-rap plays a significant role for the dam stability allowing to resist to seismic motions up to 0.5g. Such findings needed confirmation which incite to EDF to fund scaled-down experiments within the research project PEDRA (2011-2014) funded by the French Ministry of Ecological Transition. Pseudo-static tests were carried out by progressively inclining a 1/10 scaled-down dam up to failure (Figure 2).

2. Objectives
The first objective of this PhD thesis is to validate a numerical approach for the modeling of the mechanical behavior of rockfill dams with a rip –rap made of stones. To reach this goal, the pseudo-static experiments that were carried out within PEDRA will be modeled where the backfill will be associated to a continuum medium and a rip-rap to a discrete system composed of individual blocks.
The second objective is to study the influence of the rip-rap and of the blocks composing the rip-rap in the seismic resistance of rockfill dams. The loading situation will correspond to that existing on site and a pseudo-static approach will be chosen to address the problem.
The third objective is to understand what phenomena can induce the pathologies observed on site and what the reduction of the safety factor is if such events are triggered.

3. Conditions
The PhD candidate will be hired by ITASCA SAS Lyon under a CIFRE contract.
Salary: 20690 € net/year
Location: Ecole Centrale de Lyon, France / ITASCA SAS Lyon, France
Duration: 3 years
Expected PhD starting date: 1st October, 2020
Send application with curriculum at: eric.vincens@ec-lyon.fr
Closure of applications: 31th May 2020
The call will be closed before the 31th May if a relevant application is received.

Mot(s)-clé(s)

  • Comportement physique et mécanique
  • Modélisation
  • Ouvrages, patrimoine
  • Parasismique