Experimental Investigations on Tensile Strength of Sand at Low Moisture Contents

저함수비 모래의 인장강도에 대한 실험적 연구

  • Kim, Tae-Hyung (Member, Post-Doctoral Researcher, Dept. of Civ. and Envir. Engrg., Lehigh Univ.)
  • Published : 2002.06.01

Abstract

This study shows that tensile strength in moist sand clearly exists due to moisture and it is possible to simply and accurately measure the tensile strength of sands at low moisture contents. These measurements were made through the use of a newly developed direct tension apparatus and technique which are able to produce highly accurate results. The magnitudes of the tensile strengths of these moist and relatively clean sands are not equal to zero, as is widely assumed. Tensile strength increases with increasing moisture content and this trend is more noticeable at increasing relative densities. The influence of tensile strength in geotechnical problems was also examined by considering a simple rigid circular footing in sandy soil. It clearly shows that a small amount of tensile strength can significantly enhance the stability of a geotechnical system.

새롭게 개발된 직접인장시험기와 시험방법을 이용하여 습윤모래의 인장강도를 측정하였다. 본 연구를 통하여 습윤모래에 인장강도가 존재함을 분명하게 확인 할 수 있고, 저함수비 모래의 인장강도를 간단하고 정확하게 측정 가능함을 알 수 있다. 일반적으로 알고 있는 바와 달리 습윤모래의 인장강도는 영(zero)이 아님을 알 수 있다. 함수비가 (0.5 < w < 4.0%) 증가함에 따라 인장강도는 증가하는 것으로 나타났으며, 상대밀도가 (30 < $D_r$ < 70%) 증가함에 따라 인장강도가 증가하는 경향은 더욱 뚜렷하게 나타났다. 지반공학적 문제에서 습윤모래의 인장강도에 대한 영향을 조사하기 위하여 사질토지반에 설치된 원형의 강성후팅에 대한 수치해석을 실시하였다. 해석결과 미소한 인장강도를 고려하더라도 지반의 안정성이 크게 증가함을 확인할 수 있다.

Keywords

References

  1. Tensile Testing of Soils; A Literature Review Al-Hussaini, M. M.;Townsend, F. C.
  2. Geotechnical Engineering and Soil Testing Al-Khafaji, A. W.;Andersland, O. B.
  3. M.S. thesis Mechanics of granular materials at low confining stress Batiste, S.
  4. Geotechnique v.19 no.2 Drained Tests on London Clay Bishop, A. W.;Garga, V. K. https://doi.org/10.1680/geot.1969.19.2.309
  5. RRL Report LR 365 The Measurement of the Tensile Properties of Soil Cement Bofinger, H. E.
  6. Canadian Geotechnical Journal v.3 no.3 Landslide on the Toulnustone River, Quebec Conlon, R. T. https://doi.org/10.1139/t66-016
  7. Soil Mechanics for Unsaturated Soils Fredlund, D. G.;Rahardjo, H.
  8. Ph. D. thesis Moisture-Induced Tensile Strength and Cohesion in Sand Kim, T-H.
  9. Ph. D. thesis Modeling of Regolith Structure Interaction in Extraterrestrial Constructed Facilities Perkins, S.W.
  10. Powder Technology v.91 Tensile Strength of Wet Granular Materials Pierrat, P.;Caram, H. S. https://doi.org/10.1016/S0032-5910(96)03179-8
  11. The Strength of Granules and Agglomerates Rumpf, H.;Agglomeration W. A. Knepper(ed.)
  12. Powder Technology v.37 Capillary Forces-Modeling and Application in Particulate Technology Schubert, H. https://doi.org/10.1016/0032-5910(84)80010-8
  13. Journal of Aerospace Engineering v.11 no.3 Mechanics of Granular Materials at Low Effective Stresses Sture, S.;Costes, N. C.;Batiste, S. N.;Lankton, M. R.;Alshibli, K. A.;Jeremic, B.;Swanson, R. A.;Frank, M. https://doi.org/10.1061/(ASCE)0893-1321(1998)11:3(67)
  14. PLAXIS Manual (Version 7.0) Verruijt, A.;Brinkgreve, R.