Abstract
This paper focuses on the influence of the shapes of rock cores, which control the sliding or toppling behaviours in tilt tests for the estimation of rock joint roughness coefficients (JRC). When the JRC values are estimated by performing tilt tests, the values are directly proportional to the basic friction of the rock material and the applied normal stress on the sliding planes. Normal stress obviously varies with the shape of the sliding block, and the basic friction angle is also affected by the sample shapes in tilt tests. In this study, the shapes of core blocks are classified into three representative shapes and those are created using plaster. Using the various shaped artificial cores, a set of tilt tests is carried out to identify the shape influences on the normal stress and the basic friction angle in tilt tests. The test results propose a normal stress reduction function to estimate the normal stress for tilt tests according to the sample shapes based on Barton’s empirical equation. The proposed normal stress reduction functions are verified by tilt tests using artificial plaster joints and real rock joint sets. The plaster joint sets are well matched and cast in detailed printed moulds using a 3D printing technique. With the application of the functions, the obtained JRC values from the tilt tests using the plaster samples and the natural rock samples are distributed within a reasonable JRC range when compared with the measured values.
Similar content being viewed by others
Abbreviations
- a :
-
Radius of major axis of ellipse
- b :
-
Radius of minor axis of ellipse
- a e :
-
Effective area of contact surface
- α :
-
Intersection angle between sliced plane and the centre of cylinder
- β :
-
Tilting angle when sliding occurs
- b r :
-
Width of rectangular sample
- c 1, c 2, c 3 :
-
Constants of quadratic function
- d m :
-
Distance of the centre of mass from the centre of sliding plane
- e :
-
Eccentricity of block geometry
- h m :
-
Height of centre of mass from sliding plane
- h p :
-
Height of parallelogram shape sample
- h r :
-
Height of rectangular sample
- Q :
-
Weight of block
- q max :
-
Maximum vertical stress at base
- q min :
-
Minimum vertical stress at base
- q n_max :
-
Maximum normal stress at base
- q n_min :
-
Minimum normal stress at base
- x :
-
Width of contact region
References
Alejano LR, Gonzalez J, Muralha J (2012) Comparison of different techniques of tilt testing and basic friction angle variability assessment. Rock Mech Rock Eng 45:1023–1035
Bandis S, Lumsden AC, Barton N (1981) Experimental studies of scale effects on the shear behaviour of rock joints. Int J Rock Mech Min Sci Geomech 18:1–21
Barton NR (2008) Shear strength of rockfill, interfaces and rock joints, and their points of contact in rock dump design. In: Proceedings of Rock dumps 2008, Perth, pp 3–18
Barton N, Bandis S (1980) Some effects of scale on the shear strength of joints. Int J Rock Mech Min Sci Geomech Abstr 17:69–73
Barton N, Choubey V (1977) The shear strength of rock joints in theory and practice. Rock Mech 10:1–54
Baumgartner P, Stimpson B (1979) Development of a tiltable base friction frame for kinematic studies of caving at various depths. Int J Rock Mech Min Sci Geomech 16:265–267
Bray JW, Goodman RE (1981) The theory of base friction models. Int J Rock Mech Min Sci 18:453–468
Bruce IG, Cruden DM, Eaton TM (1989) Use of a tilting table to determine the basic friction angle of hard rock samples. Can Geotech J 26:474–479
Cawsey DC, Farrar NS (1976) A simple sliding apparatus for the measurement of rock joint friction. Géotechnique 26(2):382–386
Das BM (2011) Principles of foundation engineering, 7th edn. Cengage Learning, Stanford
Deere DU, Miller RP (1966) Engineering classification and index properties for intact rocks. Tech. Report. Air Force Weapons Lab., New Mexico, No. AFNL-TR: 65-116
González J, González-Pastoriza N, Castro U, Alejano LR, Muralha J (2014) Consideration on the laboratory estimate of the basic friction angle of rock joints. In: Proceedings of the 2014 ISRM European Rock Mechanics Symposium (EUROCK 2014), Vigo, Spain, pp 199–204
Gratchev I, Shokouhi A, Kim D, Stead D, Wolter A (2013) Assessment of rock slope stability using remote sensing technique in the Gold Coast area, Australia. In: Proceedings of the 18th Southeast Asian Geotechnical & Inaugural AGSSEA Conference, pp 729–734
Hencher SR (1976) Discussion on a simple sliding apparatus for the measurement of rock joint friction. Géotechnique 26:641–644
Indraratna B (1990) Development and applications of a synthetic material to simulate soft sedimentary rocks. Géotechnique 40(2):189–200
ISRM (1978) Suggested methods for the quantitative description of discontinuities in rock masses. Int J Rock Mech Min Sci Geomech Abstr 15:319–368
Itasca consulting group Inc. (2011) Fast Lagrangian analysis of continua user’s guide. Minneapolis
Janeiro RP, Einstein HH (2010) Experimental study of the cracking behaviour of specimens containing inclusions (under uniaxial compression). Int J Fract 164:83–102
Kim DH, Gratchev I, Balasubramaniam AS (2013) Determination of joint roughness coefficient (JRC) for slope stability analysis: a case study from the Gold Coast area, Australia. Landslides 10:657–664
Kim DH, Gratchev I, Balasubramaniam AS, Chung M (2015) Determination of mobilized asperity parameters to define rock joint shear strength in low normal stress conditions. In: Proceedings of the 12th ANZ conference on geomechanics, Wellington, New Zealand, pp 1145–1152
Lee YH, Carr JR, Barr DJ, Haas CJ (1990) The fractal dimension as a measure of the roughness of rock discontinuity profiles. Int J Rock Mech Min Sci Geomech Abstr 27:453–464
Maerz NH, Franklin JA, Bennett CP (1990) Joint roughness measurement using shadow profilometry. Int J Rock Mech Min Sci Geomech 27:329–343
Meyerhof GG (1953) The bearing capacity of foundations under eccentric and inclined loads. In: Proceedings of the 3rd International Conference on Soil Mechanics and Foundation Engineering (ICSMFE), Zürich, vol 1, pp 440–445
Norwegian Geotechnical Institute (2004) Forsmark site investigation, Borehole: KFM04A, Tilt testing. Technical report, SKB P-04-179, ISSN 1651-4416
Prombonas A, Vlissidis D (1994) Compressive strength and setting temperatures of mixes with various proportions of plaster to stone. J Prosthet Dent 72(1):95–100
Sagaseta C (1986) On the modes of instability of a rigid block on an inclined plane. Rock Mech Rock Eng 19:261–266
Stimpson B (1981) A suggested technique for determining the basic friction angle of rock surfaces using core. Int J Rock Mech Min Sci Geomech 18:63–65
Tse R, Cruden DM (1979) Estimating joint roughness coefficients. Int J Rock Mech Min Sci Geomech Abstr 16:303–307
USBR 6258-09 Procedure for determining the angle of basic friction (static) using a tilting table test
Wibowo J, Amadei B, Price RH, Brown SR, Sture S (1995) Effect of roughness and material strength on the mechanical properties of fracture replicas. SANDIA report, SAND94-1941, Sandia national laboratories, California 94550 the United States
Wines DR, Lilly PA (2003) Estimates of rock shear strength in part of the Fimiston open pit operation in Western Australia. Int J Rock Mech Min Sci 40:929–937
Yu X, Vayssade B (1991) Joint profiles and their roughness parameters. Int J Rock Mech Min Sci Geomech Abstr 24(4):333–336
Acknowledgments
This research was performed with the financial support of the Griffith University International Postgraduate Research Scholarship (GUIPRS) program. The authors would like to express their appreciation to anonymous reviewers for the constructive comments which have contributed to improved research and, consequently, outcomes.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kim, D.H., Gratchev, I., Hein, M. et al. The Application of Normal Stress Reduction Function in Tilt Tests for Different Block Shapes. Rock Mech Rock Eng 49, 3041–3054 (2016). https://doi.org/10.1007/s00603-016-0989-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00603-016-0989-x