Q-factor by spectral ratio technique for strata evaluations

Citation
Lp. Sarma et N. Ravikumar, Q-factor by spectral ratio technique for strata evaluations, ENG GEOL, 57(1-2), 2000, pp. 123-132
Citations number
17
Categorie Soggetti
Geological Petroleum & Minig Engineering
Journal title
ENGINEERING GEOLOGY
ISSN journal
00137952 → ACNP
Volume
57
Issue
1-2
Year of publication
2000
Pages
123 - 132
Database
ISI
SICI code
0013-7952(200006)57:1-2<123:QBSRTF>2.0.ZU;2-A
Abstract
The laboratory estimated quality factor 'Q', a function of acoustic wave sp eed (V), amplitude (A) and frequency (f), were chosen for in situ strata ev aluation of rocks of the right bank canal of upper Wardha, Maharashtra, Ind ia, using the spectral ratio technique. Eleven core samples of compact, amy gdaloidal, and vesicular basalts, were characterized by their Q values. The Q-factor determined using the spectral ratio technique with centre frequen cy of 500 kHz, is found to result in differing values for compact, amygdalo idal, and vesicular basalts over ranges 10-14, 4-6, and 2-4, respectively. The specimens belonging to amygdaloidal and vesicular basalts with secondar y minerals and calcareous intrusions in the vesicles have a very low Q valu e and a very low yield of rock mass that is not proportionate to the energy generally used in blasting operations. A correlation of Q = 0.26RQD(%) + 3 .68 between the laboratory-measured Q value and in situ rock quality design ation (RQD) (data obtained from the recovery of the exploratory borehole co re samples) provides a useful means of understanding geological strata in r ock mass recovery evaluation. The lower Q values implied higher energy requ irements for effective excavation of the rock masses. (C) 2000 Elsevier Sci ence B.V. All rights reserved.