Barton, NR 2008, 'Shear Strength of Rockfill, Interfaces and Rock Joints, and their Points of Contact in Rock Dump Design', in AB Fourie (ed.), Proceedings of the First International Seminar on the Management of Rock Dumps, Stockpiles and Heap Leach Pads
, Australian Centre for Geomechanics, Perth, pp. 3-17, https://doi.org/10.36487/ACG_repo/802_1
The peak shear strength of rock joints obtained from direct shear tests, and the peak shear strength of
rockfill, as interpreted from large-scale triaxial tests, have common non-linear strength envelopes. An
extremely low stress index test for rock joints, the tilt test, with an apparent normal stress as low as
0.001 MPa when sliding occurs, can also be performed to characterise rockfill. However for rockfill or rock
dumps, larger samples with relevant particle sizes are desirable. Some full-scale tests at a dam site in Italy,
using a 2x2x5 m tilt-shear test, were able to sample the as-compacted-as-built rockfill, with no need for
using parallel (model) grading curves with reduced-sized particles. Interfaces between the rockfill or rock
dump and eventual rock foundations, can be handled with similar shear strength estimation methods. In each
case, a low-stress index test result is extrapolated to full scale and to engineering stress level by related non-
linear strength laws. It is possible to estimate each through inexpensive characterisation. The non-linear,
stress-dependent friction angles suggest that large rock dumps with constant slope angle will have strongly
reducing factors of safety from top to bottom and from outside to inside.
Barton, N. and Choubey, V. (1977) The shear strength of rock joints in theory and practice. Rock Mechanics 1/2:1-54.
Barton, N. (1980) Evaluation of shear strength in rockfill and between rockfills and rock foundations. NGI report
53101-2, 67 p. (In Norwegian).
Barton, N. and Kjærnsli, B. (1981) Shear strength of rockfill. J. of the Geotech. Eng. Div., Proc. of ASCE, Vol. 107:
GT7: 873-891. Proc. Paper 16374, July.
Barton, N. (1999) General report concerning some 20th Century lessons and 21st Century challenges in applied rock
mechanics, safety and control of the environment. Proc. of 9th ISRM Congress, Paris, 3: 1659-1679, Balkema,
Leps, T.M. (1970) Review of the shearing strength of rockfill. J. of Soil Mech. and Found. Div., ASCE, Vol.96, No.
SM4, Proc. Paper 7394, July 1970, 1159-1170.
Linero, S. and Palma, C. (2006) Caracterización geotecnica de materiales estériles para diseño de depósitos mineros de
gran altura. (Geotechnical characterization of rock materials for design of high rock dumps). Proc. of VI th South
American Rock Mechanics Congress., Cartagena, Colombia.
Marsal, R.J. (1973) Mechanical properties of rockfill. Embankment-Dam Engineering, Casagrande Volume, eds.
Hirschfeld and Poulos, J. Wiley and Sons, New York, pp. 109-200.
Strøm, E. (1974), (1975) and (1978) NGI internal reports on triaxial testing of rockfill for various dams in Norway.
Geotechnical Issues – Strength, Stability and Seepage
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