Summary
Undrained Shear Testing of Jointed Rock
Water pressures must change inside joints undergoing shear without perfect drainage. This paper describes a new direct shear machine in which jacketed samples with oriented joints can be tested under consolidated undrained conditions with pore pressure measurement. Triaxial compression techniques for such tests are also described and typical results with intact and jointed sandstone samples are compared with results from the direct shear tests. Whereas intact specimens displayed increasing pore pressure followed by dilatancy and pore pressure decline before peak loading, the pore pressure in jointed specimens continued increasing right up to the peak load.
Zusammenfassung
Scherversuche an klüftigen Gesteinen ohne Dränung
Wasserdruck in Klüften muß sich verändern, wenn ohne perfekte Dränage Scherkraft ausgeübt wird. In der vorliegenden Arbeit wird ein neuer, direkt wirkender Scherapparat beschrieben, in welchem ummantelte Prüfkörper mit gerichteten Klüften unter Konsolidationsbedingungen ohne Dränage untersucht werden können, wobei der Porendruck gemessen wird. Es wird außerdem die Technik von Triaxialversuchen beschrieben und typische Ergebnisse mit ungestörtem und geklüftetem Sandstein werden mit Ergebnissen aus direkten Scherversuchen verglichen. Während ungestörte Proben steigenden Porendruck, gefolgt von Dilatanz, aufweisen und der Porendruck vor der Höchstbelastung nachläßt, nimmt derselbe in geklüfteten Proben bis zur Höchstbelastung ständig zu.
Résumé
Essais de cisaillement non drainé sur des échantillons de roche contenant une discontinuité
Les pressions interstitielles à l'intérieur des discontinuités doivent changer lorsqu'elles sont soumises au cisaillement et que le drainage n'est pas parfait. Cet article décrit une nouvelle machine pour essais de cisaillement direct permettant de tester, dans des conditions de consolidation non drainée, des échantillons de roche gainés comportant une discontinuité d'orientation déterminée. La machine permet la mesure de la pression interstitielle.
L'article décrit également les techniques de compression triaxiale correspondantes et des résultats typiques obtenus sur des échantillons de grès intact ou traversé par un joint sont comparés à ceux provenant des essais de cisaillement direct. Alors que les échantillons de roche intacte montrent un accroissement de la pression interstitielle suivi de dilatance et d'une réduction de pression avant que la contrainte de cisaillement maximum ne soit atteinte, la pression interstitielle dans les échantillons contenant une discontinuité croît jusqu'au droit de la contrainte de cisaillement maximum.
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References
Bieniawski, Z. T.: “Mechanism of brittle fracture of rock”, Report MEG 580 CSIR, Pretoria, South Africa, 1967.
Brace, W. F., and R. S. Martin: “A test of the law of effective stress for crystalline rocks of low porosity”, Intl. Journal of Rock Mech. and Min. Sciences, vol. 5, no. 5, p. 415 (1968).
Bruhn, R. W.: “A study of the effects of pore pressure on the strength and deformability of Berea sandstone in triaxial compression”, Corps of Engineers, Missouri River Div. Lab., Tech. Report MRDL 1–72 (1972).
Byerlee, J. D., and W. F. Brace: “Recent experimental studies of brittle fracture of rocks”, Proc. 8th Symposium Rock Mech. (AIME), p. 58 (1967).
Cornet, F., and V. Fairhurst: “Variation of pore volume in disintegrating rock”, Proc. Symposium on Percolation Through Fissured Rock, ISRM, Stuttgart, September 1972.
Deklotz, E. J., W. J. Heck, and M. J. Aldrich: “Development of equipment for studying pore pressure effects in rock”, Missouri River Div. Lab., Corps of Engineers, Tech. Report No. 3-68 (1968).
Goodman, R. E., and J. L. Dubois: “The duplication of dilatancy in the analysis of jointed rocks”, Journal Soil Mech. and Found. Div., Proc. ASCE, vol. 98, no. SM4, p. 399 (1972).
Habib, P., and Bernaix J.: “La fissuration des roches”, Proc. 1st Congress ISRM, Lisbon, vol. I, p. 185 (1966).
Handin, J., R. V. Hager, Jr., M. Friedman, and J. N. Feather: “Experimental deformation of sedimentary rocks under confining pressure: Pore pressure tests”, Bull. AAPG, vol. 47 (1963).
Heard, H. C.: “Transition from brittle fracture to ductile flow in Solenhofen limestone as a function of temperature, confining pressure; and interstitial fluid pressure”, in Rock Deformation, Memoir 79, GSA, p. 193 (1960).
Heck, W. J.: “Development of equipment for studying pore pressure effects in rock”, Proc. 10th Symposium on Rock Mechanics, (AIME), pp. 243–266 (1972).
Jaeger, J., and N. Cook: Fundamentals of Rock Mechanics, Chap. 8: “Fluid pressure and flow in rocks”, p. 195–214 (1969).
Jouanna, P.: “Effet des sollicitations mécaniques sur les écoulements dans certains milieux fissures”, Thesis for Doctor of Physical Science, Toulouse University (1972).
Jouanna, P.: “Essais de percolation au laboratoire sur des echantillons de micaschiste soumis a des contraintes”, Proc. Symposium on Percolation Through Fissured Rock, ISRM, Stuttgart 1972.
Lane, K. S.: “Engineering prob due to fluid pressure in rock”, Proc. 11th Symposium on Rock Mechanics, (AIME), p. 501 (1969).
Mesri, G., R. A. Jones, and K. Adachi: “Influence of pore water pressure on the engineering properties of rock”, Report to ARPA from University of Illinois, Dept. of Civil Engineering (1972).
Neff, T. L.: “Equipment for measuring pore pressure in rock specimens under triaxial load”, ASTM Spec. Tech. Publ. 402, p. 3 (1965).
Robinson, L. H.: “The effect of pore and confining pressure on the failure process in sedimentary rock”, Proc. 3rd Symposium on Rock Mechanics, (Qtly. Colorado School of Mines, v. 54, p. 178 (1960).
Robinson, L. H., and W. E. Holland: “Some interpretations of pore fluid effects in rock failure”, Proc. 11th Symposium on Rock Mechanics, (AIME), p. 585 (1969).
Scott, R.: Principles of Soil Mechanics, Addison Wesley, Chapter 6 (1963).
Skempton, A. W.: “The pore pressure coefficients A and B”, Geotechnique, v. 4, p. 143 (1954).
Skempton, A. W.: “Effective stress in soils concrete and rock”, Proc. Conference on Pore Pressure and Suction in Soils, Butterworth, London, p.4 (1960).
Terzaghi, K.: “Stress condition for the failure of saturated concrete and rock”, Proc. ASTM, vol. 45, p. 777 (1948).
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Goodman, R.E., Ohnishi, Y. Undrained shear testing of jointed rock. Rock Mechanics 5, 129–149 (1973). https://doi.org/10.1007/BF01238044
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DOI: https://doi.org/10.1007/BF01238044