BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Multi-directional simple shear response of soils - Giovanna Biscon
 tin (University of Cambridge)
DTSTART:20170119T113000Z
DTEND:20170119T123000Z
UID:TALK69564@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:Increasing interest in submarine slope stability\, especially 
 related to seismic loading\, was the motivation for the development of a n
 ew multi-directional simple shear device. Submarine landslides can involve
  vast areas and considerable depths. A number of the failures takes place 
 on slopes inclined 5 or less and typical soil profiles consist of almos
 t parallel layers of normally consolidated clay. The submerged slope under
  earthquake loading can be modeled using simple shear conditions to descri
 be the response of the soil. Most experimental results for fine grained so
 ils concentrate on one-dimensional response\, both for monotonic and cycli
 c tests. In addition\, experimental information on marine clays mostly com
 es from marine deposits that are now onshore and easily accessible\, such 
 as Boston Blue Clay and San Francisco Young Bay Mud\; however\, these depo
 sits have a different stress history than offshore deposits. \n\nThe new m
 ulti-directional simple shear device developed by Dr Biscontin and her stu
 dents allows loading along three independent axes\, two perpendicular hori
 zontal directions to allow any stress or strain paths in the horizontal pl
 ane\, and a third in the vertical direction. The device is also fitted wit
 h a pressure vessel providing the ability to control cell pressure and bac
 kpressure independently\, in a manner similar to triaxial systems\, for tr
 uly undrained tests. The experimental program focused on sample of clay fr
 om the Green Canyon in the Gulf of Mexico. The goal of the investigation w
 as to study the effects of anisotropy\, and multi-directional loading in p
 articular\, on the monotonic and cyclic response of normally consolidated 
 Gulf of Mexico clay. \n\nThe test results were used to develop and validat
 e constitutive models. Even if simplistic\, the SIMPLE DSS formulation can
  handle the generation of excess pore pressure as a by-product of stress-s
 train-strength relationships that require a small number of basic paramete
 rs. Examples of predictions and comparisons with test data will illustrate
  the potential of the SIMPLE DSS model. Different scenarios for slide init
 iation will be identified and predictions of slope response analyses with 
 a one-dimensional finite element code implementing SIMPLE DSS will be pres
 ented. Modelling challenges for multi-directional loading will be presente
 d.\n\nFinally\, an experimental program testing steel ballotini in simple 
 shear was paired with discontinuous element method (DEM) simulations for v
 alidation. The goal of this program is to provide conditions as similar as
  possible during all the phases of the physical and numerical processes. T
 his allows us to be confident that the information obtained at the particl
 e level from the simulations is reliable because backed by the macroscopic
  validation. The simulations\, validated by the experimental results\, pro
 vide invaluable information on the micro-mechanical response of granular m
 aterials.  \n
LOCATION:Open Plan Area\, BP Institute\, Madingley Rise CB3 0EZ
END:VEVENT
END:VCALENDAR