Shear band and landslide dynamics in submerged and subaerial slopes

Kim, Sihyun

Title:

Shear band and landslide dynamics in submerged and subaerial slopes

dc.contributor.advisor	Germanovich, Leonid N.
dc.contributor.author	Kim, Sihyun
dc.contributor.committeeMember	Frit, Hermann
dc.contributor.committeeMember	Lowell, Robert P.
dc.contributor.committeeMember	Huang, Haiying
dc.contributor.committeeMember	Yavari, Arash
dc.contributor.committeeMember	Puzrin, Alexander
dc.contributor.department	Civil and Environmental Engineering
dc.date.accessioned	2016-01-07T17:20:32Z
dc.date.available	2016-01-07T17:20:32Z
dc.date.created	2014-12
dc.date.issued	2014-11-25
dc.date.submitted	December 2014
dc.date.updated	2016-01-07T17:20:33Z
dc.description.abstract	Submarine landslides, commonly triggered by earthquakes, significantly affect tsunami wave heights. Subaerial landslides can also generate tsunamis (if the land flows into a body of water) and may be catastrophic in nature, causing human casualties and direct property damage. This work focuses on landslides associated with shear band that develops beneath the slipping mass. Accordingly, we consider a landslide as a dynamic process when a shear band emerges along the potential failure surface. Within this band, the shear strength decreases due to the softening behaviour of the particulate material. Material above the band moves downwards, causing the band to propagate dynamically. This already produces a landslide velocity before the slide reaches the post-failure stage and begins separating from the substrata and generating tsunami. However, existing models of tsunamigenic landslides assume zero initial slide velocity. Previous analyses of the catastrophic shear band propagation in slopes of normally- and over-consolidated sediments have shown that a relatively short initial failure zone is sufficient to cause a full-scale landslide. For the shear band to propagate, the energy produced in the body by an incremental propagation of the shear band must exceed the energy required for the propagation. This consideration separates the shear band growth into progressive (stable) and catastrophic (dynamic) stages and treats the band growth as a true physical process rather than an instantaneously appearing discontinuity. This work considers a dynamic shear band problem formulated within the framework of the Palmer and Rice’s [1973] approach. We obtain the exact, closed-form solution for the shear band and landslide velocities as well as for the spatial and temporal distributions of strain and material velocity. This solution assesses when the slide fails due to the limiting condition near the propagating tip of the shear band. We also obtain a simple asymptotic solution, which is compared to the exact solution. In the case of submerged slopes, the obtained solutions are used in landslide and tsunami height analyses. Our results suggest that the conventional static approach to the slope stability analysis leads to a significant underestimation of the slide size (volume). In most cases, the volumes of catastrophic slides are roughly twice the volumes of progressive slides. For submerged slides, this dynamic effect further manifests itself in increasing the tsunami magnitude compared to the static case.
dc.description.degree	Ph.D.
dc.format.mimetype	application/pdf
dc.identifier.uri	http://hdl.handle.net/1853/54245
dc.language.iso	en_US
dc.publisher	Georgia Institute of Technology
dc.subject	Submarine landslides
dc.subject	Shear band propagation
dc.subject	Fracture mechanics
dc.title	Shear band and landslide dynamics in submerged and subaerial slopes
dc.type	Text
dc.type.genre	Dissertation
dspace.entity.type	Publication
local.contributor.corporatename	School of Civil and Environmental Engineering
local.contributor.corporatename	College of Engineering
relation.isOrgUnitOfPublication	88639fad-d3ae-4867-9e7a-7c9e6d2ecc7c
relation.isOrgUnitOfPublication	7c022d60-21d5-497c-b552-95e489a06569
thesis.degree.level	Doctoral