00731161

Component

https://doi.org/10.3141/1548-07

http://scholar.google.com...abuz&publication_year=1996

An acoustic emission (AE) system with eight channels of recording was used to monitor progressive failure of a weak sandstone in plane-strain compression. The recorded waveforms were analyzed for event location and source mechanism. In the quantitative assessment of acoustic emission, a localized event is idealized as a point source of displacement discontinuity. The point source can be modeled as the combination of body forces that would produce the same elastic wave-field as the defect. The assumed condition of self-equilibrium requires each body force to be paired with an equal and opposite force to form a dipole of forces called a seismic moment tensor. In this study, the seismic moment tensor of each event was evaluated and the source mechanisms were determined through a calibration of the sensors, where the first peak of the signal recorded by an AE sensor was assumed to correspond to the first peak of the normal displacement at the sensor. The microseismic events generated during progressive failure of the sandstone were characterized as being caused predominantly by shear slip. Within a certain portion of the post-peak regime where 110 events were captured, the slip displacement was 0.0217 mm from the seismic estimate and 0.0335 mm from the global measurement. This suggests that the AE technique could be used to estimate displacement along a localized zone of failure where microseismic activity takes place.

This paper appears in Transportation Research Record No. 1548, Small-Magnitude Measurements in Geotechnical Engineering.

English

p. 46-50

1996

Transportation Research Record

0309059178

Figures (8) ; References (15)

Acoustic emission tests; Dislocation (Geology); Failure; Sandstones; Shear zones; Slip surfaces; Strain (Mechanics)

Plane strain

Geotechnology; Highways; I42: Soil Mechanics

TRIS, TRB

Feb 3 1997 12:00AM

• ANALYSIS OF METHODS USED IN TIME DOMAIN REFLECTOMETRY RESPONSE
• BEHAVIOR OF SHAFT-SAND INTERFACE FROM LOCAL MEASUREMENTS
• CHARACTERIZATION OF GRANULAR SYSTEMS BY DIGITAL SIGNAL PROCESSING OF LOW STRAIN WAVE RESPONSE
• CYCLIC SIMPLE SHEAR APPARATUS FOR LOW-STRAIN SOIL TESTS
• DEVELOPMENT OF CYCLIC TRIAXIAL APPARATUS WITH BROAD FREQUENCY AND STRAIN RANGES
• INSTRUMENTATION FOR LATERALLY LOADED MODEL PILES
• LOW STRAIN DYNAMIC SHEAR MODULUS OF CEMENTED SAND FROM CONE PENETRATION TEST RESULTS
• MEASUREMENT OF SOIL RESILIENT PROPERTIES USING NONCONTACTING PROXIMITY SENSORS
• MICRODEFORMATIONS IN SANDS BY DIGITAL IMAGE PROCESSING AND ANALYSIS
• RADIAL STRAIN MEASUREMENTS IN RESONANT COLUMN AND TORSIONAL SHEAR TESTS
• SMALL- AND HIGH-STRAIN MEASUREMENTS OF IN SITU SOIL PROPERTIES USING THE SEISMIC CONE PENETROMETER
• SOIL PARTICLE SIZE ANALYSIS USING X-RAY ABSORPTION