WORKSHOPS ON CRACKS IN ROCKS

The workshop focused on the modeling of physical properties of rocks in terms of the theory of composites, with the direct observation of cracks and voids, and with the estimation of the distributions of certain crack properties. Voids in rocks can be separated into 2 groups: first group which consists of cavities and crack systems characterized by a relatively high aspect ratio (alpha, the thickness to diameter ratio of the cavity or crack (greater than or equal to 0.1) and a second class characterized by true cracks with aspect ratio alpha less than or equal to 10 to the power -3. Research is reported in which sectioned rocks were subjected to uniaxial compressive stress to observe the onset of dilatancy. A refined observational method whereby 100 mu thin sections yield 3-dimensional images of cracks under the electron microscope as described, as well as indirect methods of observation which yield crack distributions. The use of surface conductivity as a tool for the study of microcracks is outlined, and work concerned with the spatial orientation of cracks as demonstrated by the effect of polarization direction on the seismic velocity in laboratory samples of dilatant rock. Details are given of research on the effects of dry and saturated dilatant cracks on the elastic and seismic properties of flawed bodies; and of research which determined the effects of flat cracks on the electrical conductivity of a solid. Theoretical work on dilatant rock behavior is briefly reviewed, and the development of theory applicable to pores and cracks is discussed. Other research briefly reported here covers work on the effects of temperature and pressure on various material properties of rocks, the behavior of fissured rock, the localization of deformation, and computer modeling to determine the strength of cracked rocks.

  • Corporate Authors:

    American Geophysical Union

    1909 K Street, NW, Division of Hydrology
    Washington, DC  United States  20006
  • Authors:
    • Hoenig, A
  • Publication Date: 1976-1

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Filing Info

  • Accession Number: 00134027
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jun 23 1976 12:00AM