EXPLORATION OF THE KINEMATICS OF THE 1963 VAJONT SLIDE, ITALY, USING A NUMERICAL MODELLING TOOLBOX — IJEGE
 
 
You are here: Focus and scope Issues from 2005 to 2017 International Conference on Vajont 1963-2013 / Proceedings - Thoughts and analyses after 50 years since the catastrophic landslide Topic 6 - The Vajont rockslide EXPLORATION OF THE KINEMATICS OF THE 1963 VAJONT SLIDE, ITALY, USING A NUMERICAL MODELLING TOOLBOX
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EXPLORATION OF THE KINEMATICS OF THE 1963 VAJONT SLIDE, ITALY, USING A NUMERICAL MODELLING TOOLBOX



Abstract:
The Vajont Slide has been studied for half a century, yet questions about its kinematics and dynamics still remain. Application of state-of-the-art numerical techniques aids in understanding the slide’s mechanical behaviour. In the current paper, we use four two- and three-dimensional finite element, distinct element, and lattice-spring modelling codes in a toolbox approach to conduct a forensic, exploratory investigation of the kinematics of the slide. We examined the influence of rock mass properties and friction along the failure surface using the 2D finite element code. Preliminary results indicate that weaker units within the sliding mass deformed more than stronger units, and that a Prandtl wedge zone of transition developed between the active upper and passive lower blocks of the slide mass in the west. The difference between the biplanar western sliding surface and the more circular eastern surface proves to be significant in terms of stability. Models suggest a critical friction angle of approximately 18°, above which the slope is stable. The 2D distinct element modelling results indicate that both failure surface morphology and block size are important. Planar and arc-shaped failure surfaces are most unstable, whereas rough undulating surfaces are stable. As block size increases, overall slope stability increases and a lower friction angle along the failure surface is required to initiate sliding. Block kinematics were further investigated using a 3D distinct element code. This numerical code illustrated the controls of bounding structural features such as the Col Tramontin Fault and Erto Syncline, as well as block size, on the failure. Finally, preliminary simulations in a new 3D lattice-spring code show that crack clusters developed, and became concentrated in the transition zone between the back and seat of the chair-shaped failure surface.

Authors:
Andrea Wolter - Simon Fraser University - Burnaby, British Columbia, Canada
Mohsen Havaej - Simon Fraser University - Burnaby, British Columbia, Canada
Luca Zorzi - Golder Associates- Burnaby, British Columbia, Canada
Doug Stead - Simon Fraser University - Burnaby, British Columbia, Canada
John J. Clague - Simon Fraser University - Burnaby, British Columbia, Canada
Monica Ghirotti - Alma Mater Universitá di Bologna - Bologna, Italy
Rinaldo Genevois - Universitá degli Studi di Padova - Padova, Italy
Keywords
Vajont Slide; kinematics; numerical modelling; toolbox approach; finite element; distinct element; lattice-spring
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