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SUMMARY:Experiments with rock: observations of fracture
DTSTART:20130524T140000
DTEND:20130524T153000
DTSTAMP:20260506T080525Z
UID:99536d830ba2e3ec8dd2237b20c4aaa33da93c1705fd9aafa9d3de6c
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Labuz  (head of the CE dept. of the university of Minne
 apolis)\nIt is evident from a strength test conducted on a specimen of roc
 k that failure is associated with initiation and propagation of fracture.
   The rock may deform uniformly until a critical condition is reached\, a
 nd then deformation localizes in a zone that opens and/or slides.  Becaus
 e of the presence of the fracture\, a structural size effect on the overal
 l response appears\, and energy released from the failure process can be s
 udden or gradual.  Controlling failure is often necessary to achieve safe
  operations of underground mines\, while promoting failure efficiently is 
 a concern in excavating and drilling.  Thus\, the conditions to initiate 
 and propagate a fracture are often needed for proper designs in rock.\nDet
 ails of tensile fracture from flexural tests are reported based on the opt
 ical methods of speckle interferometry and image correlation\, which provi
 de high-resolution measurements of crack displacements.  Acoustic emissio
 n\, which are elastic waves emitted during the fracture process\, deliver 
 information on location and mechanism of microcracking.  Fracture charact
 eristics such as critical crack opening and process-zone length are highli
 ghted.\nAn interpretation of shear fracture is discussed in relation to pl
 ane strain compression tests\, where growth of a failure plane is observed
  at various stress states.  Displacement measurements\, AE locations\, an
 d thin-section microscopy allowed direct and indirect observations of in-p
 lane propagation\, and fracture mechanics was used to determine the shear 
 fracture toughness of the rock.\nWill  be followed by a lecture of A. Fer
 rari "An experimental and constitutive investigation on the chemo-mechanic
 al behaviour of a clay"
LOCATION:GC B1 10.
STATUS:CONFIRMED
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