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SUMMARY:Introduction to FEM/DEM technology and its application to model of
  Excavation Damaged Zone (EDZ) in anisotropic rock formation
DTSTART:20130228T121500
DTEND:20130228T131500
DTSTAMP:20260506T205314Z
UID:e201e3e97e0655d6e8ea1709bbe5aad2e81822dba6434bd46b8c3a2b
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Giovanni Grasselli\nThe combined finite/discrete element
  method (FEM/DEM) is a numerical technology that combines DEM algorithms\,
  which capture the interaction and fracturing of different solids\, with F
 EM principles that describe the elastic deformation of discrete bodies. Da
 mage and failure of rock material is simulated in FEM/DEM by explicitly mo
 delling crack initiation and propagation using principles of non-linear el
 astic fracture mechanics.\nThe purpose of this presentation is three-fold:
 \n(i) to present the basic concepts of the hybrid finite-discrete element 
 method (FEM/DEM)\;\n(ii) to illustrate the new approaches that have been i
 ntroduced into the FEM/DEM technology to model layered materials\; and\n(i
 ii) to demonstrate the effectiveness of this new modelling approach in sim
 ulating the development of fractures around a tunnel excavated in layered 
 rock formation.\nIn this context\, the term excavation damaged zone (EDZ) 
 refers to the volume of rock close to an underground opening that has expe
 rienced irreversible deformation due to the excavation and where new fract
 ures have occurred. With respect to the original host rock\, EDZ is charac
 terized by a reduced mechanical strength and a significant increase in its
  flow and transport properties. Thus\, for both rock support design and pe
 rmeability studies it is important to estimate the extent and the geometry
  of the EDZ\, which is also influenced by the type of material and its int
 ernal microstructure. In particular\, it has been observed that the EDZ in
  layered rock formations is heavily affected by the anisotropic mechanical
  response of the material due to the presence of bedding planes and it can
 not be properly modeled using a continuum approach.\nThis presentation wil
 l also present how a transversely isotropic elastic constitutive law was i
 mplemented into FEM/DEM to account for the anisotropy in global elastic mo
 dulus\, while procedures to incorporate a distribution of preferentially o
 riented defects and the presence of bedding planes were devised to capture
  the anisotropic strength of metamorphic and sedimentary rocks. \nFinally
 \, an example of model calibration and simulated fracture patterns around 
 circular excavations will be then discussed in the context of the theory o
 f brittle rock failure and analyzed with reference to the EDZ formation me
 chanisms observed at the Mont Terri Underground Research Laboratory\, Swit
 zerland.\nBio sketch:\nDr. Giovanni Grasselli is a full faculty member at 
 the University of Toronto\, Canada. He holds an undergraduate degree in Ci
 vil Engineering (1995) from the University of Parma\, Italy\, and a PhD in
  Rock Mechanics (2001) from the Swiss Federal Institute of Technology (EPF
 L)\, Lausanne\, Switzerland.  His doctoral thesis ‘‘Shear Strength of
  Rock Joints based on Quantified Surface Description’’ was awarded wit
 h the 2004 ISRM Rocha Medal.  Previously to join University of Toronto\, 
 he has been research fellow at the Imperial College London (UK)\, and at t
 he Sandia National Laboratories (USA). He has served as associate director
  of the Geomechanis Research Centre at Mirarco (Canada) in 2005 and of the
  Lassonde Institute for Mining at the University of Toronto in 2007-2009.
LOCATION:GC C330
STATUS:CONFIRMED
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