Anelastic strain recovery and the Kaiser effect retention span in the Carnmenellis Granite, UK

Authors
Citation
Sp. Barr et Dp. Hunt, Anelastic strain recovery and the Kaiser effect retention span in the Carnmenellis Granite, UK, ROCK MECH R, 32(3), 1999, pp. 169-193
Citations number
21
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geological Petroleum & Minig Engineering
Journal title
ROCK MECHANICS AND ROCK ENGINEERING
ISSN journal
0723-2632 → ACNP
Volume
32
Issue
3
Year of publication
1999
Pages
169 - 193
Database
ISI
SICI code
0723-2632(199907/09)32:3<169:ASRATK>2.0.ZU;2-T
Abstract
Knowledge of in-situ stress in rock masses is essential for mining and civi l engineering design and the Kaiser effect method of stress determination p rovides an economical alternative to currently applied investigation techni ques. A practical problem associated with this method is the loss of the Ra iser effect over time during the process of anelastic strain recovery, but a direct relationship is observed between anelastic strain recovery and the number of acoustic emissions. The behaviour is modelled here using the Kel vin and Burger rheological models. for the stags of creep during uniaxial l aboratory loading, anelastic strain recovery and the loss of the Raiser eff ect, with constants being calculated and compared for samples loaded under geological and laboratory conditions. It is found that the loss of the KE a t low stress levels compares directly with the process of anelastic strain recovery and fits the Burger model over the time scales of interest. A diff erence between primary and secondary (undercored samples) recovery is demon strated with a slower recovery for primary relaxation and with samples take n from geological stress environments recovering more slowly than those loa ded under laboratory conditions, for all stress levels tested.