Some new insights of rock failure under dynamic loading

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Abstract

Experimental investigations are conducted to study dynamic fracture behaviour of sedimentary, igneous and metamorphic rocks. The notched semi-circular bending method (NSCB) has been employed to determine fracture parameters using a split Hopkinson pressure bar (SHPB). The time to fracture, crack speed and velocity of the flying fragments are measured by strain gauge, crack propagation gauge and high-speed photography. Dynamic crack initiation toughness is determined from the dynamic stress intensity factor at the time to fracture, and dynamic crack growth toughness is derived by dynamic fracture energy at a specific crack speed. This study reveals clearly that (i) dynamic crack initiation and growth toughness increase with increasing loading rate and crack speed; (ii) kinetic energy of the flying fragments increases with increasing impact speed of the striker; and, (iii) dynamic fracture energy increases rapidly with increasing crack speed. A semi-empirical rate-dependent fracture model is proposed.

Original languageEnglish
Title of host publicationISRM VietRock 2015 International Workshop
Publication statusPublished - 2015
EventISRM VietRock 2015 International Workshop - Hanoi, Vietnam
Duration: 12 Mar 201513 Mar 2015

Conference

ConferenceISRM VietRock 2015 International Workshop
CountryVietnam
CityHanoi
Period12/03/1513/03/15

Keywords

  • Dynamic Loading
  • Energy
  • Failure Mechanisms
  • Fracture Toughness
  • Rock Dynamics

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