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Incremental propagation of discrete compaction bands: Acoustic emission and microstructural observations on circumferentially notched samples of Bentheim
Author(s) -
Vajdova Veronika,
Wong TengFong
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl017750
Subject(s) - compaction , acoustic emission , transverse plane , overburden pressure , materials science , shear (geology) , stress (linguistics) , geotechnical engineering , displacement (psychology) , composite material , geology , shear stress , cylinder stress , fracture (geology) , mineralogy , structural engineering , psychology , linguistics , philosophy , engineering , psychotherapist , ultimate tensile strength
To simulate how compaction localization may develop from structural and stress heterogeneity, we studied in the laboratory the influence of a stress concentration due to a V‐shaped circumferential notch in a cylindrical sample of Bentheim sandstone. Conventional triaxial experiments at confining pressure of 300 MPa were conducted. Acoustic emission activity was recorded, and each sample was deformed to a different stage and subsequently retrieved for microstructural observations. Our data indicate that compaction bands initiated from the notch tips and propagated by sequential increments as “anti‐cracks”. The transverse propagation of a compaction band was inferred to be faster than the axial displacement rate by 2 orders of magnitude. Energy dissipated for compaction band formation was estimated to be comparable to the shear fracture energy for shear band propagation.