CHEN YONGup, YAO XIAO-XINup, XIE HONG-SENup2. 1981: STUDIES ON FRACTURE OF GABBRO. Acta Seismologica Sinica, 3(3): 321-330.
Citation: CHEN YONGup, YAO XIAO-XINup, XIE HONG-SENup2. 1981: STUDIES ON FRACTURE OF GABBRO. Acta Seismologica Sinica, 3(3): 321-330.

STUDIES ON FRACTURE OF GABBRO

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  • Published Date: August 31, 2011
  • Triaxial compression with 3=1.3kb is applied to samples of Jinan gabbro and the development of microcracks is studied with a microscope. It is found that under low stresses, the microcracks occur within the crystal grains of the rock minerals and their orientation is determined principally by the configuration of the crystals. When the applied stress reaches about 80% of the ultimate strength, the cracks become more concentrated in the central part near one diagonal of the sample. At this time, there appear a few microfalts, which cut through several crystal grains. The orientation of these microfaults depends obviously on the direction of the external stress, which makes an angle less than 40 with the direction of maximum stress1. The volume changes as wellaas VP and Vs in the rock samples are also measured. It is found that the development of the microcracks in rock samples and their influence on physical propertied of the rock are dependent on the dimensions of the crystal grains.
  • [1] J. D. Byerlee&D. Lockner, Acoustic emission during fluid injection in rock, Proc. 1st conf. On acoustic emission (microseismic activity in geological structure and material), 1977.

    [2] W. F. Brace, B. V'. Jr Pauldiug & C. H. Scliolz, Dilataucy in the fracture of crysalliue rock, J. Geophys, Res., 71, 3939——3953, 1966,

    [3] B. T. Brady, Theory of earthquakes, Part 1. A scale independent. theory of rock failure, PAGEOPH, 112, 699——725 1974.

    [4] M. Frieudman Fracture in rocks, Rev. Geophys. Space Pleysics., 13, 353——358, 1975.

    [5] F. Rummel & C.Fairhurst, Determination of the post——failure behaviour of brittle rock using a servo——vontrolled testing machine, Rock Mech, 2, 189——204, 1970.

    [6] F. Runnnel, H. J. Aiheid, & C. Fruhn, Dilatancy and fracture induced velucity changes in rock and their relation to friction sliding, PAGEOPH, 116, 743——764, 1978.

    [7] D. K. Hallbauer, H. Wabner. & N. G. W., Cook, Microxopic and mechanical behaviouroof quartzite specimen in stiff triaYial conxpression test, Int. J. Rock Mech. Min Sci 10, 713——726, 1973.

    [8] H. Koide & K. Hosliino, Development of microfracture in experimentally deformed rocks, (preliminary report), Eartlrquake, 20, 85——97, 1970.

    [9] V. I. Mjachkin, W. F. Brace, G. A. Sobolev, & J. H. Dieterich, Two models for earthquake forerunners, PAGEOPH, 113, 169——181, 1975.

    [10] W. A. Olsson, Microfracturing and faulting in limestone, Tectonophysics, 24, 277——285. 1974.

    [11] S. Peng & A. M. Johnson, Crack growth and faulting in cylindrical specimen of Chelmsford granite, In, t. J. Rock Mec7t.. illin Sci 9, 37——86, 1972.

    [12] C. H. Scholz, Experimental study of the fray turfing process in brittle rock, J. Geophys. Res., 73, 1447——1454, 1968

    [13] Eve. S. Sprunt & W. F. Brace, Direct observation of naicrocavities in crystalline rocks, Int. J. Rock lllecle. hlin. Sei., 11, 139——150, 1974.

    [1] J. D. Byerlee&D. Lockner, Acoustic emission during fluid injection in rock, Proc. 1st conf. On acoustic emission (microseismic activity in geological structure and material), 1977.

    [2] W. F. Brace, B. V'. Jr Pauldiug & C. H. Scliolz, Dilataucy in the fracture of crysalliue rock, J. Geophys, Res., 71, 3939——3953, 1966,

    [3] B. T. Brady, Theory of earthquakes, Part 1. A scale independent. theory of rock failure, PAGEOPH, 112, 699——725 1974.

    [4] M. Frieudman Fracture in rocks, Rev. Geophys. Space Pleysics., 13, 353——358, 1975.

    [5] F. Rummel & C.Fairhurst, Determination of the post——failure behaviour of brittle rock using a servo——vontrolled testing machine, Rock Mech, 2, 189——204, 1970.

    [6] F. Runnnel, H. J. Aiheid, & C. Fruhn, Dilatancy and fracture induced velucity changes in rock and their relation to friction sliding, PAGEOPH, 116, 743——764, 1978.

    [7] D. K. Hallbauer, H. Wabner. & N. G. W., Cook, Microxopic and mechanical behaviouroof quartzite specimen in stiff triaYial conxpression test, Int. J. Rock Mech. Min Sci 10, 713——726, 1973.

    [8] H. Koide & K. Hosliino, Development of microfracture in experimentally deformed rocks, (preliminary report), Eartlrquake, 20, 85——97, 1970.

    [9] V. I. Mjachkin, W. F. Brace, G. A. Sobolev, & J. H. Dieterich, Two models for earthquake forerunners, PAGEOPH, 113, 169——181, 1975.

    [10] W. A. Olsson, Microfracturing and faulting in limestone, Tectonophysics, 24, 277——285. 1974.

    [11] S. Peng & A. M. Johnson, Crack growth and faulting in cylindrical specimen of Chelmsford granite, In, t. J. Rock Mec7t.. illin Sci 9, 37——86, 1972.

    [12] C. H. Scholz, Experimental study of the fray turfing process in brittle rock, J. Geophys. Res., 73, 1447——1454, 1968

    [13] Eve. S. Sprunt & W. F. Brace, Direct observation of naicrocavities in crystalline rocks, Int. J. Rock lllecle. hlin. Sei., 11, 139——150, 1974.
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