00000nam 2200000za 4500 9.840158 CaOODSP 20221107151756 cr ||||||||||| 170721s1966 oncad ob f000 0 eng d CaOODSP eng n-cn--- M38-8/15E-PDF M38-8/15 Barron, K. Glass insert stressmeters [electronic resource] / K. Barron, Fuels and Mining Practice Division. Ottawa : Queen's Printer, 1966. p. 287-299 : charts, ill. Reprint series ; RS 15 Cover title. "Reprinted from Society of Mining Engineers, December 1965." Historical publication digitized from print 2017 [by Natural Resources Canada]. Includes bibliographical references. "The glass insert stressmeter, or photoelastic stressmeter, is an instrument designed to determine stress changes occurring in rocks. It has several potential advantages over other such devices in that it is a biaxial device, it is simple and it is cheap to make. The object of this study was to assess the behaviour of the meter under biaxial loads and to examine some of the problems associated with measurement and interpretation of the fringe pattern. This assessment has been carried out by comparing theoretical and laboratory behaviour of the meter. It has been shown that: a) There are certain optimum measuring points in the meter at which measurements should be made for best accuracy. The position of the points depends on the ratio, n, of the biaxial stresses. b) The meter's sensitivity can be assumed to be independent of the rock modulus E provided that the rock modulus is < 2.5 x 10 6 psi and not, as previous works have assumed, if E < 5 x 10 6 psi. c) There are several methods of separating the principal stresses; some of these are unsatisfactory. A new method is proposed and discussed. d) The meter sensitivity decreases as the ratio of the biaxial stresses approaches unity; the accuracy thus also decreases. e) The axes of symmetry of the fringe pattern give an excellent indication of applied stress direction. f) Laboratory calibrations are in good agreement with theory"--p. 497. gccst Rocks gccst Physics gccst Measurement Canada. Natural Resources Canada. Canada. Department of Energy, Mines and Resources. Canada. Mines Branch. Reprint series - Dept. of Energy, Mines and Resources, Mines Branch ; RS 15 (CaOODSP)9.834843 PDF 3.63 MB https://publications.gc.ca/collections/collection_2017/rncan-nrcan/M38-8/M38-8-15-eng.pdf 300094