LOGIN TO YOUR ACCOUNT

Username
Password
Remember Me
Or use your Academic/Social account:

CREATE AN ACCOUNT

Or use your Academic/Social account:

Congratulations!

You have just completed your registration at OpenAire.

Before you can login to the site, you will need to activate your account. An e-mail will be sent to you with the proper instructions.

Important!

Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version of the site upon release.

Thank you for your patience,
OpenAire Dev Team.

Close This Message

CREATE AN ACCOUNT

Name:
Username:
Password:
Verify Password:
E-mail:
Verify E-mail:
*All Fields Are Required.
Please Verify You Are Human:
fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Shang, J; Hencher, SR; West, LJ (2016)
Publisher: Springer Verlag
Languages: English
Types: Article
Subjects:
Geological discontinuities have a controlling influence for many rock-engineering projects in terms of strength, deformability and permeability, but their characterisation is often very difficult. Whilst discontinuities are often modelled as lacking any strength, in many rock masses visible rock discontinuities are only incipient and have tensile strength that may approach and can even exceed that of the parent rock. This fact is of high importance for realistic rock mass characterisation but is generally ignored. It is argued that current ISRM and other standards for rock mass characterisation, as well as rock mass classification schemes such as RMR and Q, do not allow adequately for the incipient nature of many rock fractures or their geological variability and need to be revised, at least conceptually. This paper addresses the issue of the tensile strength of incipient discontinuities in rock and presents results from a laboratory test programme to quantify this parameter. Rock samples containing visible, natural incipient discontinuities including joints, bedding, and mineral veins have been tested in direct tension. It has been confirmed that such discontinuities can have high tensile strength, approaching that of the parent rock. Others are, of course, far weaker. The tested geological discontinuities all exhibited brittle failure at axial strain less than 0.5 % under direct tension conditions. Three factors contributing to the tensile strength of incipient rock discontinuities have been investigated and characterised. A distinction is made between sections of discontinuity that are only partially developed, sections of discontinuity that have been locally weathered leaving localised residual rock bridges and sections that have been ‘healed’ through secondary cementation. Tests on bedding surfaces within sandstone showed that tensile strength of adjacent incipient bedding can vary considerably. In this particular series of tests, values of tensile strength for bedding planes ranged from 32 to 88 % of the parent rock strength (intact without visible discontinuities), and this variability could be attributed to geological factors. Tests on incipient mineral veins also showed considerable scatter, the strength depending upon the geological nature of vein development as well as the presence of rock bridges. As might be anticipated, tensile strength of incipient rock joints decreases with degree of weathering as expressed in colour changes adjacent to rock bridges. Tensile strengths of rock bridges (lacking marked discolouration) were found to be similar to that of the parent rock. It is concluded that the degree of incipiency of rock discontinuities needs to be differentiated in the process of rock mass classification and engineering design and that this can best be done with reference to the tensile strength relative to that of the parent rock. It is argued that the science of rock mass characterisation may be advanced through better appreciation of geological history at a site thereby improving the process of prediction and extrapolating properties.
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • Aitkenhead N, Barclay WJ, Brandon A, Chadwick RA, Chisholm JI, Cooper AH, Johnson EW (2002) The Pennines and adjacent areas, 4th edn. British Geological Survey, Nottingham, pp 8-14
    • Arthurton RS, Johnson EW, Mundy DJC (1988) Geology of the country around Settle. Memoir of the British Geological Survey, Sheet 60 (English and Wales)
    • Barla G, Innaurato N (1973) Indirect tensile testing of anisotropic rocks. Rock Mech Rock Eng 5:215-230
    • Brzovic A, Villaescusa E (2007) Rock mass characterization and assessment of block-forming geological discontinuities during caving of primary copper ore at the EI Teniente mine, Chile. Int J Rock Mech Min Sci 44:565-583
    • Cravero M, Iabichino G (2004) Analysis of the flexural failure of an overhanging rock slab. Int J Rock Mech Min Sci 41(3):605-610
    • Dan DQ, Konietzky H, Herbst M (2013) Brazilian tensile strength tests on some anisotropic rocks. Int J Rock Mech Min Sci 58:1-7
    • Deere DU (1968) Geological considerations. Chapter 1. In: Stagg KG, Zienkiewicz OC (eds) Rock mechanics in engineering practice. Wiley, New York, pp 1-20
    • Deere DU, Deere DW (1989) Rock quality designation (RQD) after twenty years. Contract Report GL-89-1, US Army Corps of Engineers, 67p plus Appendix
    • Erarslan N, Williams DJ (2012) Experimental, numerical and analytical studies on tensile strength of rocks. Int J Rock Mech Min Sci 49:21-30
    • Hashiba K, Fukui K (2014) Effect of water on the deformation and failure of rock in uniaxial tension. Rock Mech Rock Eng 47:1-11
    • Hawkes I, Mellor M, Gariepy S (1973) Deformation of rocks under uniaxial tension. Int J Rock Mech Min Sci Geomech Abstr 10:493-507
    • Hencher SR (2006) Weathering and erosion processes in rock - implications for geotechnical engineering. In: Proceedings symposium on Hong Kong soils and rocks, March 2004. Institution of Mining, Metallurgy and Materials and Geological Society of London, pp 29-79
    • Hencher SR (2012) Practical engineering geology. Spon Press, Taylor & Francis, Oxon
    • Hencher SR (2014) Characterizing discontinuities in naturally fractured outcrop analogues and rock core: the need to consider fracture development over geological time. Geol Soc Lond Spec Publ Adv Study Fract Reserv 374:113-123
    • Hencher SR (2015) Practical rock mechanics. Spon Press, Taylor and Francis, Oxon
    • Hencher SR, Knipe R (2007) Development of rock joints with time and consequences for engineering. In: Proceeding of the 11th congress of the international society of rock mechanics, Lisbon, Portugal
    • Hencher SR, Richards LR (2015) Assessing the shear strength of rock discontinuities at laboratory and field scales. Rock Mech Rock Eng 48:883-905
    • Hoek E (2007) Practical rock engineering. p 342. http://www. rocscience.com
    • ISRM (1978a) Suggested methods for the quantitative description of discontinuities in rock masses. Int J Rock Mech Min Sci Geomech Abstr 15:319-368
    • ISRM (1978b) Suggested methods for determining tensile strength of rock materials. Int J Rock Mech Min Sci Geomech Abstr 15:99-103
    • Khan AS, Irani FK (1987) An experimental study of stress wave transmission at a metallic-rock interface and dynamic tensile failure of sandstone, limestone and granite. Mech Mater 6:285-292
    • King WBR (1934) The lower palaeozoic rocks of Austwick and Horton-in-Ribblesdale, Yorkshire. Q J Geol Soc Lond 90:7-31
    • Kwansniewski M (2009) Testing and modelling of the anisotropy of tensile strength of rocks. Proceeding of the international conference on rock joints and jointed rock masses Arizona, United States
    • Li HB, Li JC, Bo L, Li JR, Li SQ, Xia X (2013) Direct tension test for rock material under different strain rates at quasi-static loads. Rock Mech Rock Eng 46:1247-1254
    • Liao JJ, Yang MT, Hsieh HY (1997) Direct tensile behaviour of a transversely isotropic rock. Int J Rock Mech Min Sci 34(5):837-849
    • Liu JF, Chen L, Wang C, Man K, Wang L, Wang J, Su R (2014) Characterizing the mechanical tensile behaviour of Beishan granite with different experimental methods. Int J Rock Mech Min Sci 69:50-58
    • Mier JGM, Shi C (2002) Stability issues in uniaxial tensile tests on brittle disordered materials. Int J Solids Struct 39:3359-3372
    • Okubo S, Fukui K (1996) Complete stress-strain curves for various rock types in uniaxial tension. Int J Rock Mech Min Sci 33(6):549-556
    • Paronuzzi P, Serafini W (2009) Stress state analysis of a collapsed overhanging rock slab: a case study. Eng Geol 108:65-75
    • Pells PJN (1993) Uniaxial strength testing. In: Hudson JA (ed) Comprehensive rock engineering, vol 3. Pergamon Press, Exeter, pp 67-85
    • Perras MA, Diederichs M (2014) A review of the tensile strength of rock: concepts and testing. Geotech Geol Eng 32:525-546
    • Saiang D, Malmgren L, Nodlund E (2005) Laboratory tests on shotcrete-rock joints in direct shear, tension and compression. Rock Mech Rock Eng 38(4):275-297
    • Soper NJ, Dunning FW (2005) Structure and sequence of the Ingleton Group, basement to the central Pennines of northern England. Proc Yorks Geol Soc 55:241-261
    • Stevenson IP, Gaunt GD (1971) Geology of the country around Chapel-en-le-Frith. Memoir of the Geological Survey of Great Britain, Sheet 99 (English and Wales)
    • Tating F, Hack R, Jetten V (2015) Weathering effects on discontinuity properties in sandstone in a tropical environment: case study at Kota Kinabalu, Sabah Malaysia. Bull Eng Geol Environ 74:427-441
    • Turichshev A, Hadjigeorgiou J (2014) Experimental and numerical investigations into the strength of intact veined rock. Rock Mech Rock Eng 48:1897-1912
    • Turkington AV, Paradise TR (2005) Sandstone weathering: a century of research and innovation. Geomorphology 67:229-253
    • Wang W (2009) Rock mass mechanics (English edition). Central South University Press, Changsha
    • Waters CN, Aitkenhead N, Jones NS, Chisholm JI (1996) Late Carboniferous stratigraphy and sedimentology of the Bradford area, and its implications for the regional geology of northern England. Proceeding of the Yorkshire Geological Society 51(Part 2):87-101
  • No related research data.
  • Discovered through pilot similarity algorithms. Send us your feedback.

Share - Bookmark

Cite this article