Virtual MEchanics GAthering -MEGA- Seminar: A transition from sub-Rayleigh anticrack to supershear crack propagation in snow slab avalanche release

Thumbnail

Event details

Date and time 06.05.2021 16:1517:30  
Place and room
https://epfl.zoom.us/s/84678428267 Passcode: 174387
Online https://epfl.zoom.us/s/84678428267
Speaker Bertil Trottet (SLAB, EPFL)
Category Conferences - Seminars
Abstract Snow slab avalanches are released following anticrack propagation in highly porous weak snow layers buried below cohesive slabs. The volumetric collapse of the weak layer leads to the closure of crack faces followed by the onset of frictional contact. On the basis of snow fracture experiments, full-scale avalanche measurements, and numerical simulations, we report the existence of a transition from sub-Rayleigh anticrack to supershear crack propagation involving the Burridge--Andrews mechanism. Remarkably, the loss of frictional resistance during collapse enables this transition to occur for shear-to-normal stress ratio lower than the static friction coefficient. This switch of propagation drivers represents a new paradigm in our understanding of snow slab avalanches presenting fundamental similarities with strike-slip earthquakes.

Bio Bertil Trottet is a PhD student at the Snow and Avalanche Simulation Laboratory, graduated with a BSc and MSc in Mechanical Engineering from EPFL.
His research focuses on the release mechanics of slab avalanches.
 

Practical information

  • General public
  • Free

Organizer

  • MEGA.Seminar Organizing Committee

Tags

Solids Structures Fluids

Share