"Stress distribution around a pilot hole during overcoring was investigated. A study of axial strain on the borehole surface was undertaken. Two-dimensional epoxy resin models were prepared and stress frozen in a centrifuge. The stress-frozen models were examined under a direct-viewing polariscope. The magnitude of axial strain and the effect of strain relaxation on the pilot hole were measured on blocks of brittle materials. Factors contributing to discing of core during the overcoring operation were investigated and a mechanism of failure postulated. The loading conditions simulating in situ, core and bit pressures were applied individually to the brittle models and axial strain readings were noted. Axial strain was found to be at a significant value and radical differences in stress levels were found within the overcored zone"--Abstract, page i.
Scott, James J.
Beveridge, Thomas R. (Thomas Robinson), 1918-1978
Spokes, Ernest M., 1916-1995
Parry, Myron G.
M.S. in Mining Engineering
University of Missouri at Rolla
vi, 75 pages
© 1966 Varakantham Sreedhar Reddy, All rights reserved.
Thesis - Open Access
Rock mechanics -- Mathematical models
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Reddy, Varakantham Sreedhar, "A study of stress distribution and measurement of axial strain around a pilot hole during overboring" (1966). Masters Theses. 5743.