Acoustic emissions during deformation of jointed rock
As an aid to understanding and monitoring the behavior of jointed rock masses, we have done a series of experiments on samples of Grouse Canyon tuff containing sawcut joints. The tuff was selected because it is under consideration as a disposal medium for nuclear wastes. The samples were instrumented to measure axial and transverse displacements and AE rates. Testing was done in a servocontrolled machine at displacement rates of 2 x 10{sup -5} in/sec, and confining pressures ranging from 1500 to 6000 psi. Four modes of slip on joints were identified. First, stable sliding accompanied by a steady rate of AE. Second, stick-slip with a sharp drop in load, large displacements but no premonitory AE or slip. Third, stick-slip, as in mode 2, but with premonitory AE and slip. Fourth, stable stick-slip where the load dropped and the displacements increased but the process was slow and culminated in stable sliding. Mode 4 exhibited premonitory AE and slip and after the event, a steady rate of AE during sliding. In all cases where premonitory slip or stable sliding occurred there was a corresponding occurrence of AE, indicating slip is related to damage to the joint surfaces and adjacent material. Monitoring AE would be a useful method of detecting slip and the extent of slip in modes 1, 3, and 4. Increasing slip rate leads to increasing AE rate. However, mode 2 stick-slip appears to be undetectable by this method.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 60537
- Report Number(s):
- CONF-811036-; TRN: 84:027573
- Journal Information:
- Series on Rock and Soil Mechanics, Vol. 8; Conference: 3. conference on acoustic emission/microseismic activity in geologic structures and materials, University Park, PA (United States), 5-7 Oct 1981; Other Information: PBD: 1984
- Country of Publication:
- United States
- Language:
- English
Similar Records
Dynamic strength of rocks
Roles of nanoclusters in shear banding and plastic deformation of bulk metallic glasses