FACTORS AFFECTING THE ACOUSTIC EMISSION RESPONSE OF TRIAXIALLY COMPRESSED ROCK

Experimental study of the acoustic emission associated with inelastic processes such as cracking and slip on crack surfaces during deformation of rocks offers an excellent method of investigating the mechanism of brittle fracture. Investigations were carried out on acoustic emissions from buntsandstone specimens compressed triaxially at confining pressures ranging from atmospheric pressure to the brittle-ductile transition pressure. The acoustic emissions were monitored in the frequency band of 100-300 khz and during the complete range of specimen deformation including the post-failure region. Experimental results show that during the pre-peak stress region, the acoustic emission rate (aer) increases with increasing axial stress (or deformation) and undergoes a sharp change at a stress level corresponding to the yield strength of the test specimen. A rapid decrease of aer in the first half of the post-failure region followed by a rapid increase in it in the second half was noted for all specimens tested at confining pressures up to 100 mpa, which is the transition pressure of buntsandstone. This variation in aer has been interpreted as being due to the formation of fault segments in the first half of the post-failure region and cracking of material bridges ahead of the fault segments leading to the coalescence of fault segments in the second half.(a) (TRRL)

  • Availability:
  • Corporate Authors:

    Pergamon Press, Incorporated

    Headington Hill Hall
    Oxford OX30BW,   England 
  • Authors:
    • Gowd, T N
  • Publication Date: 1980-8

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Filing Info

  • Accession Number: 00324668
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Sep 16 1981 12:00AM