Ground stress determinations in Canada
Tóm tắt
Stress determinations with the biaxial (Doorstopper) and the triaxial strain cell of the C. S. I. R., South Africa, are discussed and show that the triaxial cell is the more desirable instrument if good rock conditions exist. Vertical and average horizontal stresses in Canada are similar in magnitude to those from other parts of the earth's crust and show that vertical stresses are related to weight of overburden and average horizontal stresses increase in most of the cases with 0.407 kg/cm2 per metre of depth. More data are necessary to make any prediction for the average horizontal stress beyond a depth of 800 m. Stress determinations and a tectonic analysis show that the unravelling of the geological stress-strain history allows some prediction of principal stress directions, but the attached uncertainties due to gaps in documentation require proof by stress determinations.
Tài liệu tham khảo
Panek, L. A.: Calculation of the Average Ground Stress Components from Measurements of the Diametral Deformation of a Drill Hole. U. S. Dept. of Interior, RI 6732 (1965).
Leeman, E. R.: The Doorstopper and Triaxial Rock Stress Measuring Equipment. J. S. Afr. Inst. Min. Met., Vol. 69, pp. 305–339 (1969).
Gray, W. M., and N. A. Toews: Analysis of Accuracy in the Determination of the Ground Stress Tensor by Means of Borehole Devices, in: Status of Rock Mechanics — Ninth Symp. on Rock Mech., Colorado School of Mines, April 1967, pp. 45–78. Pub. by the Society of Mining Engineers of A. I. M. E. (1968).
Herget, G.: First Experiences with the C. S. I. R. Triaxial Strain Cell for Stress Determinations. Int. J. Rock Mech. Min. Sci. & Geomech. Abstr., Vol. 10, pp. 509–522 (1973).
Gray, W. M., and N. A. Toews: Optimization of the Design and Use of a Triaxial Strain Cell for Stress Determination. A. S. T. M. Symp., Philadelphia, June 1973.
Gray, W. M., and N. A. Toews: Analysis of Variance Applied to Data Obtained by Means of a Six-Element Borehole Deformation Gauge for Stress Determination. 15th U. S. Symp. on Rock Mechanics, Custer State Park, South Dakota (1973).
Herget, G.: Variation of Rock Stress with Depth at a Canadian Mine. Int. J. Rock Mech. Min. Sci., Vol. 10, pp. 37–51 (1973).
Hast, N.: The State of Stress in the Upper Part of the Earth's Crust. Tectonophysics, Vol. 8, pp. 189–211 (1969).
Lowdon, J. A., C. H. Stockwell, H. W. Tipper, and R. K. Wanless: Age Determinations and Geological Studies. Geol. Survey Canada, Paper 62-17 (1963).
Geological Survey of Canada, Isotropic Age Map of Canada, 1256A (1970).
Bielenstein, H. U., and G. H. Eisbacher: In-Situ Stress Determinations and Tectonic Fabric at Elliot Lake, Ontario. Proc. 5th Can. Rock Mech. Symp., Ecole Polytechnique (1970).
Ambrose, J. W.: Exhumed Paleoplains of the Precambrian Shield of North America. Am. J. Sci., Vol. 262, pp. 817–857.
Coates, D. F., and F. Grant: Rock Mechanics Investigations 1963/64 at the MacLeod Mine, Algoma Ore Properties Division, Algoma Steel Corp. Unpublished report.
Yu, Y.: Rock Mechanics Investigations at the MacLeod Mine, 1965. Unpublished report.
Zahary, G., and D. F. Coates: Rock Mechanics Investigations 1964/65 at MacLeod Mine, Algoma Ore Properties, Wawa, Ontario. Unpublished report (1966).
Herget, G.: Tectonic Fabric and Current Stress Field at an Iron Mine in the Lake Superior Region. Proc. 24th Int. Geol. Cong., Section 13, pp. 241–248 (1972).