The seismic techniques of ultrasonic probing and acoustic emissions were used to study mode I (tensile) crack propagation. Displacement-controlled fracture tests were performed on wedge-loaded, double cantilever beam specimens of Charcoal granite. The relative attenuation of surface waves delineated the end of the inelastic region. The locations of the microseismic events indicated that the major acoustic activity was along the microscopically (100 multiplied by magnification) observed crack plane. Tensile fracture in rock can be characterized by an effective crack length, composed of a traction free portion (approximated by the compliance crack length), and a so-called ligament process zone (the region of major acoustic activity). For Charcoal granite, the process zone was over 10% of the effective length.
|Original language||English (US)|
|Title of host publication||Unknown Host Publication Title|
|Publisher||Soc for Experimental Mechanics Inc|
|Number of pages||5|
|State||Published - Dec 1 1986|