Dynamic Frictional Behavior of Saw-cut Rock Joints Through Shaking Table Test

진동대 시험에 의한 편평한 암석 절리면의 동적 마찰거동 특성

  • Published : 2006.02.01

Abstract

In recent years, not only the occurrences but the magnitude of earthquakes in Korea are on an increasing trend and other sources of dynamic events including large-scale construction, operation of hi띤-speed railway and explosives blasting have been increasing. Besides, the probability of exposure fir rock joints to free faces gets higher as the scale of rock mass structures becomes larger. For that reason, the frictional behavior of rock joints under dynamic conditions needs to be investigated. In this study, a shaking table test system was set up and a series of dynamic test was carried out to examine the dynamic frictional behavior of rock joints. In addition, a computer program was developed, which calculated the acceleration and deformation of the sliding block theoretically based on Newmark sliding block procedure. The static friction angle was back-calculated by measuring yield acceleration at the onset of slide. The dynamic friction angle was estimated by closely approximating the experimental results to the program-simulated responses. As a result of dynamic testing, the static friction angle at the onset of slide as well as the dynamic friction angle during sliding were estimated to be significantly lower than tilt angle. The difference between the tilt angle and the static friction angle was $4.5\~8.2^{\circ}$ and the difference between the tilt angle and the dynamic friction angle was $2.0\~7.5^{\circ}$. The decreasing trend was influenced by the magnitude of the base acceleration and inclination angle. A DEM program was used to simulate the shaking table test and the result well simulated the experimental behavior. Friction angles obtained by shaking table test were significantly lower than basic friction angle by direct shear test.

Keywords

Dynamic frictional behavior;Rock joints;Shaking table test;Friction angle

References

  1. Newmark, N.M., 1965, Effects of earthquakes on dams and embankments, Geotcchnique 15, 139-160 https://doi.org/10.1680/geot.1965.15.2.139
  2. Oden, J.T., Martins, J.A.C., 1985, Models and computational methods for dynamic friction phenomena, Computer Methods in Applied Mechanics and Engineering 52, 527-634 https://doi.org/10.1016/0045-7825(85)90009-X
  3. Kramer, S.L., Smith, M.W., 1997, Modified Newmark model for seismic displacements of compliant slopes, Journal of Geotechnical and Geoenvironmental Engineering 123.7, 635-644 https://doi.org/10.1061/(ASCE)1090-0241(1997)123:7(635)
  4. Lin, J.S., Whitman, R.V., 1983, Decoupling approximation to the evaluation of earthquake induced plastic slip in earth dams, Earthquake Engineering and Structural Dynamics 11, 667-67 https://doi.org/10.1002/eqe.4290110506
  5. Wartman, J., 1999, Physical model studies of seismically induced deformation in slopes, Ph.D. Dissertation, University of California, Berkeley, U.S.A
  6. Patton, F.D., 1966, Multiple modes of shear failure in rock, Proceedings of the 1 st Congress of the ISRM, Lisbon, 509-513
  7. Augello, A.J., 1997, Seismic response of solid-waste landfills, Ph.D. Dissertation, University of California, Berkeley, U.S.A
  8. Jaeger, J.C., 1971, Friction of rocks and stability of rock slopes, Geotechnique 21, 97-134 https://doi.org/10.1680/geot.1971.21.2.97
  9. Gazatas, G., Uddin, N., 1994, Permanent deformation on pre-existing sliding surfaces in dams, Journal of Geotechnical Engineering 120.11, 2041-2061 https://doi.org/10.1061/(ASCE)0733-9410(1994)120:11(2041)
  10. Barton, N., 1973, Review of a new shear strength criterion for rock joints, Engineering Geology 7, 287-332 https://doi.org/10.1016/0013-7952(73)90013-6
  11. Kramer, S.L., 1996, Geotechnical earthquake engineering, Prentice Hall, New Jersey
  12. Van, L., 1991, Seismic deformation analyses of earth dams: A simplified method, Soil mechanics laboratory report No. SML 91-01, California Institute of Technology