Journal of the Earthquake Engineering Society of Korea (한국지진공학회논문집)

Earthquake Engineering Society of Korea (한국지진공학회)
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The effects of End Platens on Effective Stresses in Resonant Column (RC) Specimens during Consolidation

공진주 시험기 단부가 압밀중인 시료의 유효응력에 미치는 영향

  • Published : 2008.02.29
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Abstract

The objective of this study is to investigate the effects of rigid end platens on effective stresses in soil mass during consolidation. The friction between the teeth of top cap/base pedestal and the specimen during consolidation decreases the radial and tangential effective stresses in RC specimens. However, it is unpractical to measure the effective stresses in the soil specimen. Two approaches were used to evaluate the state of stress in RC specimens during consolidation. First, careful measurements were made of small strain shear modulus, $G_{max}$ in specimens with carefully controlled void ratios and stress histories, to infer the state of stress. And second, a finite element analysis was performed to analytically evaluate the effect of various soil parameters on the state of stress in RC specimens during consolidation. By combining these experimental and analytical results, an example was performed to predict the average state of stress in RC specimens during consolidation.

이번 연구의 목적은 시험기의 단부가 압밀중인 시료의 유효응력에 미치는 영향을 연구함에 있다. 압밀중에 시험기 단부와 시료사이의 마찰은 공진주 시험기 시료의 반경 및 접선방향의 유효응력을 감소시킨다. 하지만, 시료의 유효응력을 측정하는 것은 실용적이지 않다. 압밀중 시험기 시료 유효응력 상태를 평가하기 위해 두 가지 접근이 이루어졌다. 첫째, 응력상태를 추측하기 위해 신중하게 조절된 간극비와 응력이력을 가진 시료의 최대 전단 탄성계수가 측정되었다. 둘째, 여러 가지 시료 정수가 압밀중 시험기 시료의 응력상태에 미치는 영향을 분석하기 위해 유한요소법이 수행되었다. 이러한 실험 결과와 분석적 기법결과를 종합해서 압밀중 공진주 시험시료에서의 평균주응력을 예측하는 해석적 예제를 수행하였다.

Keywords

References

  1. Perloff, W. H. and Pombo, L. E., "End restraint effects in the triaxial test," Proceedings of the 7th Int. Conference on Soil Mechanics and Foundation, Mexico 1, 1969, pp. 327-333
  2. Saada, A. S., and Townsend, F. C., "State of the Art: Laboratory strength testing of soils," Laboratory Shear Strength of Soil, ASTM 740, Young, R. N. and Townsend, F. C., Editors, ASTM, 1981, pp. 7-77
  3. Bancroft, D., "The velocity of longitudinal waves in cylindrical bars," Physics Review, 59, April, 1941
  4. McNeil, R. L., A study of the propagation of stress waves in sand, Technical Report No. AFWL-TR-65-180, Air force weapon laboratory, March, 1966, 223pp
  5. Anderson, D. G., and Woods, R. D., "Time-dependent increase in shear modulus of clay," Journal of Geotechnical Engineering, ASCE, Vo. 102, No. 5, 1976, pp. 525-537
  6. Wu, S., Gray, D. H., and Richart, F. E., "Capillary effects on dynamic modulus of sands and silts," Journal of Geotechnical Engineering, ASCE, Vol. 110, No 9, 1984, pp. 1427-1447
  7. Bae, Y. S., "Modeling soil behavior in large strain resonant column and torsional shear tests," Utah State University, Logan, Utah, 2007, 184pp
  8. Hardin, B. O., "The nature of stress-strain behavior for soils," Proceedings of Earthquake Engineering and Soil Dynamics, Pasadena, California, ASCE, I, 1978, pp. 3-90
  9. Afifi, S. S., and Richart, F. E., Jr., "Stress-history effects on shear modulus of soils," Soils and Foundations, Vo. 13, No. 1, 1973, pp. 77-95
  10. Janbu, N., "Soil compressibility as determined by oedometer and triaxial tests," Proceedings of the 3rd European Conference on Soil Mechanics., Wiesdaden 1, 1963, pp. 19-25
  11. American Society for Testing and Materials, "Standard Test Methods for Modulus and Damping of Soils by the Resonant-Column Method," Annual Book of ASTM Standards, Vol. 04.08, D4015-92, Philadelphia, Pennsylvania, 2000. pp. 462-482
  12. PLAXIS: Finite Element Code for Soil and Rock Analyses, Version 7. Edited by R.B.J Brinkgreve and P.A. Vermeer. A.A. Balkema Publishers, Rotterdam, Netherlands, 1998
  13. Yu, P., and Richart, F. E., "Stress ratio effects on shear modulus of dry sands," Journal of Geotechnical Engineering, ASCE, Vol. 110, No. 3, 1984, pp. 331-345 https://doi.org/10.1061/(ASCE)0733-9410(1984)110:3(331)