The Kaiser effect in rocks: principles and stress estimation techniques

✍ Scribed by Lavrov, A.

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 461 KB
• Volume: 40
• Category: Article
• ISSN: 0148-9062
• DOI: 10.1016/s1365-1609(02)00138-7

✦ Synopsis

Irreversible deformation of rocks is accompanied by the Kaiser effect involving acoustic emission (AE). AE activity increases dramatically as soon as the largest previously experienced stress level is exceeded, similar to strain hardening in ductile materials. The Kaiser effect can be considered as a basis for stress measurements in rocks. This phenomenon is characterized by complexity which is the reason for disputable data interpretation procedures. A review of experimentally established features of the Kaiser effect, including those under a triaxial state of stress, is given. Mechanisms and theoretical models of the phenomenon are discussed. Stress measurement techniques based on the Kaiser effect in core specimens and in rocks around a borehole are explained; their strengths and weaknesses are analyzed. The necessity and the directions for future research are outlined. The analysis given should facilitate future applications of the Kaiser effect and improve the correctness of data interpretation.