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Rock Mechanics and Rock Engineering

, Volume 24, Issue 1, pp 1–29 | Cite as

Model experiments for propellant embedded rock anchors

  • H. H. Einstein
  • F. S. Jeng
Article

Summary

Propellant embedded anchors can be used to secure offshore platforms by rapidly anchoring them in seafloor rock. Field tests conducted by the U.S. Navy showed inconsistent results. A more promising approach seems to be modelling of anchor penetration and pullout resistance in jointed rock based on first principles.

In this paper, physical model tests are described with which the physical phenomena are investigated and which will serve as a basis for predictive analytical models. The laboratory experiments, conducted with fasteners to model the anchors and with jointed and intact rock models made from gypsum, showed that basic intact material properties, joint configuration and individual joint properties influence penetration and pullout resistance. If the behavior is brittle, penetration is accompanied by cracking, otherwise ductile continuum deformation occurs. Jointing affects cracking in that closer joint spacing restricts cracking to fewer “joint bounded plates” but increases the number of cracks in the individual plate. The increased cracking intensity leads to a reduced pullout resistance.

For purposes of analytical modelling, one can therefore, in a first step, build upon established relations between intact meterial, joint geometry and individual joint characteristics.

Keywords

Gypsum Joint Spacing Jointed Rock Intact Rock Continuum Deformation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Baecher, G. B., Einstein, H. H. (1981): Size effect in rock testing. Geophys. Res. Lett. 18 7.Google Scholar
  2. Bandis, G., Lumsden, A., Barton, N. (1981): Experimental studies of scale effects on the shear behavior of rock joints. Int. J. Rock Mech. Mining Sci. 18 6.Google Scholar
  3. Barton, N., Lien, N., Lunde, J. (1974): Engineering classification of rock masses for the design of tunnel supports. Rock Mechanics 6/4.Google Scholar
  4. Beard, R. M. (1984): Testing of a conical rock fluke for the 20k propellant embedded anchor; status report. Technical Memorandum 42-84-01, Naval Civil Engineering Laboratory, Port Hueneme, CA, U. S. A.Google Scholar
  5. Colp, J. L. (1968): Teradynamics: A study of projectile penetration of natural earth materials. Sandia Laboratory, Albuquerque, Sc-DR-68-215. 61 p.Google Scholar
  6. Einstein, H. H., Baecher, G. B., Hirschfeld, R. C. (1970): The effect of size or the strength of a brittle rock. Proc. 2nd Int. Congress on Rock Mechanics.Google Scholar
  7. Einstein, H. H., Hirschfeld, R. C. (1973): Model studies on mechanics of jointed rock. J. ASCE Soil Mech. Found. Div. 99/SM3.Google Scholar
  8. Einstein, H. H., Baecher, G. B., Beneziano, D., O'Reilly, K. P. (1983): The effect of discontinuity persistence on rock slope stability. Int. J. Rock Mech. Mining Sci. 20/5.Google Scholar
  9. Einstein, H. H., Jeng, F. S. (1988): Propellant embedded anchors in rock. MIT Report on 2nd Phase or Research Performed for Naval Civil Engineering Laboratory.Google Scholar
  10. Engelder, T. (1987): Joints and shear fractures in rock. In: Fracture Mechanics of Rock (Athanson, B. K., ed.). Academic Press.Google Scholar
  11. Gerber, W. (1987): Theorie zum Eintreiben und Verankern von Bolzen in Beton. Bauingenieur 62, 213–218.Google Scholar
  12. Hilti (1989): Technical documentation on fasteners and fastener guns.Google Scholar
  13. Hoek, E., Brown, E. T. (1980): Underground excavation in rock. Institution of Mining and Metallurgy, London.Google Scholar
  14. Joseph, P. G., Einstein, H. H. (1987): Rock modelling using the centrifuge. Report to AFESC, Contract DACA 88-86-D-0013.Google Scholar
  15. Kulander, B. R., Dean, S. L. (1985): Hackle plume geometry and joint propagation dynamics. Proc. Int. Symp. on Fundamentals of Rock Joints, Björkliden.Google Scholar
  16. McClintock, F. A., Argon, A. S. (eds.) (1962): An introduction to the mechanical behavior of materials. Section I, Chap. 14. School of Engineering, M. I. T., Cambridge.Google Scholar
  17. Miller, M. H., Sikarskie, D. L. (1968): On the penetration of rock by threedimensional indenters. Int. J. Rock Mech. Mining Sci. 5/5, 375–398.Google Scholar
  18. Nelson, R. A. (1968): Modelling a jointed rock mass. S. M. Thesis, MIT.Google Scholar
  19. Sanio, H. P. (1985): Prediction of the performance of disk cutters in anisotropic rock. Int. J. Rock Mech. Mining Sci. 22/3, 153–161.Google Scholar
  20. Thorne, C. P. (1977): The allowable loadings of foundations on shale and sandstone in the Sydney region, Part 3: Field test results. Paper presented to Sydney Group of Australian Geomech. Soc.Google Scholar
  21. True, D., Young, S., Einstein, H. H. (1991): Field tests on propellant embedded anchors (in preparation).Google Scholar
  22. Wadeworth, J. F., Beard, R. M. (1980): Propellant-embedded anchors; prediction of holding capacity in coral and rock seafloors. Technical Note N-1595, Naval Civil Engineering Laboratory, Port Hueneme, CA, U. S. A.Google Scholar
  23. Young, C. W. (1969): Depth prediction for earth penetrating projectiles. J. ASCE Soil Mech. Fourd, Div. 95/3, 803–817.Google Scholar
  24. Zhou, G. V. (1988): Penetration of fastener projectiles into construction materials. Ph. D. Thesis, University of Durham, U. K.Google Scholar

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • H. H. Einstein
    • 1
  • F. S. Jeng
    • 1
  1. 1.Department of Civil EngineeringM.I.T.CambridgeUSA

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