Advertisement

Clays and Clay Minerals

, Volume 22, Issue 5–6, pp 397–408 | Cite as

Fabric-Property Relationships in fine Granular Materials

  • Arshud Mahmood
  • James K. Mitchell
Article

Abstract

In this investigation fabric-property relationships were studied in a silty fine sand sized crushed basalt—an artificial ‘soil’ that has previously been used to simulate lunar soil. The fabric was characterized by measuring preferred orientations of grains, and pore size distribution was determined by mercury intrusion porosimetry. When deposited by pouring, the grains acquired strong preferred orientations in the horizontal direction and formed pores between 1 and 30 μm dia. Densification by static or dynamic compaction resulted in near random grain arrangement and pore sizes between 0.1 and 10 μm dia.

Strength in direct shear and one-dimensional compressibility with the associated lateral stresses were measured. The strength was up to 30 per cent higher when the sample was sheared normal to the preferred orientation of grains than when the shearing was parallel to the orientation direction. This is to be expected, as shearing across the preferentially oriented grains should involve breakage or reorientation of many grains. At a given initial void ratio the compressibility of statically compacted specimens was larger (up to 30 per cent higher axial strain) than that of dynamically compacted specimens at very low stresses. At higher stresses both samples exhibited equal compressibility, suggesting that the grains become more randomly arranged at low void ratios (comparing samples of equal initial void ratios).

Résumé

Dans ce travail on a étudié les propriétés d’arrangement particulaire d’un basalte broyé à la dimension d’un sable fin limoneux, un “sol” artificiel qui avait été utilisé auparavant pour simuler un sol lunaire.

L’arrangement a été caracterisé en mesurant l’orientation préférentielle des grains et la distribution des pores a été déterminée par porosimétrie au mercure. Quand le dépôt est obtenu en faisant couler la poudre, les grains acquièrent de fortes orientations préférentielles dans la direction horizontale et forment des pores dont le diamètre est compris entre 1 et 30 μm. L’augmentation de densité par compaction statique ou dynamique entraîne un arrangement granulaire presque au hasard et des diamètres de pores compris entre 0,1 et 10 μm.

La contrainte principale de cisaillement et la compressiblité monodimensionnelle ont été mesurées, avec les contraintes latérales associées. Lors du cisaillement normal à l’orientation préférentielle des grains la contrainte était supérieure jusqu’à 30 pour cent à ce qu’elle était lots du cisaillement parallèle à la direction d’orientation. Ce résultat n’est pas inattendu puisque le cisaillement à travers des grains orientés préférentiellement doit entraîner une cassure ou une réorientation de nombreux d’entre eux. Pour un indice de vide initial donné, la compressibilité à faible pression d’échantillons compactés par voie statique est plus grande que celle d’échantillons compactés par voie dynamique (compactabilité axiale jusqu’à 30 pour cent supérieure). Aux pressions plus élevées les deux échantillons ont des compressibilités égales, ce qui suggère que les grains sont arrangés plus au hasard pour les indices de vide bas (la comparaison portant sur des échantillons à indice de vide initial égal).

Kurzreferat

In dieser Untersuchung wurden die Beziehungen zwischen Gefüge und Eigenschaften an einem schluffig-feinsandigen, gemahlenen Basalt untersucht—einem künstlichen ‘Boden’, der schon früher zur Simulation des Mondbodens benutzt wurde. Das Gefüge wurde durch Messung der bevorzugten Kornorientierung gekennzeichnet und die Porengrößenverteilung durch Quecksilberporosimetrie bestimmt. Wenn ihre Ablagerung durch Schütten erfolgte, nahmen die Körner eine streng bevorzugte Orientierung in horizontaler Richtung ein und bildeten Poren zwischen 1 und 30 Ém im Durchmesser. Statische oder dynamische Verdichtung führte zu einer nahezu zufälligen Kornanordnung und zu Porengrößen zwischen 0,1 und 10 Ém im Durchmesser.

Der Widerstand bei direkter Abscherung und die eindimensionale Kompressibilität mit den zugehörigen seitlichen Spannungen wurden gemessen. Der Scherwiderstand war bis zu 30 Prozent größer, wenn die Scherbeanspruchung der Probe senkrecht zur bevorzugten Orientierung der Körner erfölgte, als bei Abscherung parallel zur Orientierungsrichtung. Dies entspricht der Erwartung, da Abscherung senkrecht zu bevorzugt orientierten Körnern Bruch und Reorientierung vieler Körner beinhalten sollte. Bei einem gegebenen anfänglichen relativen Porenvolumen war die Kompressibilität statisch verfestigter Proben bei sehr geringen Drucken größBer (bis Zu 30 Prozent höhere axiale Spannung) als die dynamisch verfestigter Proben. Bei höheren Drucken wiesen beide Proben gleiche Kompressibilität auf, was darauf hindeutet, daß die Körner bei niedrigem relativem Porenvolumen eine zufälligere Anordnung erhalten (wenn Proben gleicher anfänglicher Hohlraumanteile verglichen werden).

Резюме

В этом исследовании изучались соотношения «структура-свойства» в илистом измельченном до размера песка базальте, искусственной почве, которая прежде применялась для имитации почвы луны. Характеристика структуры определялась измерением преобладающей ориентации зёрен, а распределение размеров пор определялось ртутной интрузионной порозиметрией. При насыпании зёрна принимали строго преобладающую ориентировку в горизонтальном направлении, образуя поры диаметром от 1 до 30 μм. Статическое или динамическое уплотнение давало почти беспорядочное распределение и размеры пор были между 0,1 и 10 μм. диам. Измерялись прочность на прямой срез и одно-размерная сжимаемость со связанными с нею латеральными напряжениями. Прочность была до 30% выше, когда образец срезался нормально по преобладающей ориентировке зёрен, чем при срезке параллельно направлению ориентировки. Это и предполагалось, так как срез через зёрна преобладающей ориентировки должен был вызывать разрыв или изменение ориентировки многих зёрен; при данном исходном коэффициенте пустотности сжимаемость статически сжатых образцов была больше (до 30% выше осевого усилия), чем динамически сжатых образцов при очень низких напряжениях. При более высоких напряжениях сжимаемость обоих образцов была одинаковой; это указывало на то, что зёрна располагались более беспорядочно при низких коэффициентах пустотности (когда сравнивались образцы с одинаковыми исходными коэффициентами пустотности).

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Ahmed, S., Lovell, C. W., Jr. and Diamond, S. (1974) Pore sizes and strength of compacted clay: Proc. Am. Soc. Civ. Engrs. Vol. 100, No. GT4, J. Geotechnical Div. April 1974, pp. 407–425.Google Scholar
  2. Arthur, J. R. F. and Menzies, B. K. (1972) Inherent aniso-tropy in a sand: Geotechnique 22 (1), 115–128.CrossRefGoogle Scholar
  3. ASTM (1972) Standard Method of Test for Relative Density of Cohesionless Soils. Amer. Soc. for Test, and Mater., Method D2049, Standards, Pt. 11.Google Scholar
  4. Barden, L., Sides, G. R. and Karunaratne, J. P. (1970) A microscopic examination of clay structure: Proc. 2nd Southeast Asian Conf. Soil Eng., Singapore, June 1970.Google Scholar
  5. Brewer, R. (1964) Fabric and Mineral Analysis of Soils, 470 pp. Wiley, New York.Google Scholar
  6. Casagrande, A. (1932) The structure of clay and its importance in foundation engineering: In Contributions to Soil Mechanics 1925–1940, pp. 72–126. Originally appeared in J. Boston Soc. Civil Engrs., April.Google Scholar
  7. Dapples, E. C. and Rominger, J. F. (1945) Orientation analysis of fine-grained clastic sediments: A report of progress: J. Geol. 53, 246–261.CrossRefGoogle Scholar
  8. Diamond, S. (1970) Pore size distributions in clays: Clays and Clay Minerals 18, 7–23.CrossRefGoogle Scholar
  9. Hardcastle, J. H. (1972) Factors influencing compressibility and permeability-electrolyte concentration relationships in clayey sediments. Ph.D. Dissertation, University of California, Berkeley.Google Scholar
  10. Jizba, Z. V. (1971) Mathematical Analysis of Grain Orientation, Chap. 13: In Procedures in Sed. Petr. (Edited by Carver, R. E.) Wiley, New York.Google Scholar
  11. Klock, G., Boersma, L. and DeBacker, L. (1969) Pore size distributions as measured by the mercury intrusion method and their use in predicting permeability: Proc. Soil Sci. Soc. Am. 33, 12–15.CrossRefGoogle Scholar
  12. Krinsley, D. and Smalley, I. (1973) Shape and nature of small sedimentary quartz particles: Science 180, 1277–1279.CrossRefGoogle Scholar
  13. Lafeber, D. and Willoughby, D. (1971) Fabric symmetry and mechanical anisotropy in natural soils: Ist Australia-New Zealand Conference on Geomechanics, pp. 165–175.Google Scholar
  14. Lambe, T. W. (1953) The structure of inorganic soil: Procs. ASCE, Separate No. 315, October, 1953.Google Scholar
  15. Mahmood, A. (1973) Fabric-mechanical property relationships in fine granular soils. Dissertation Submitted in Partial Satisfaction of the Requirements for the Degree of Doctor of Philosophy in Engineering at the University of California, Berkeley.Google Scholar
  16. Matalucci, R., Shelton, J. and Abel- Hady, M. (1969) Grain orientation in Vicksburg loess: J. Sed. Petrol. 39, 969–979.CrossRefGoogle Scholar
  17. Mitchell, J. K. (1956) Fabric of natural clays and its relation to engineering properties: Procs., Highway Research Board 35, 693–713.Google Scholar
  18. Moore, C. A. (1971) Effect of mica on K0 compressibility of two soils: Proc. Am. Soc. Civ. Engrs. 97 (SM9), J. Soil Mech. Found. Eng., 1275–1292.Google Scholar
  19. Morgan, J. R. and Gerrard, C. M. (1971) Behavior of sands under surface loads: Proc. Am. Soc. Civ. Engrs. 97 (SM12), 1675–1699.Google Scholar
  20. Morgenstern, N. and Tchalenko, J. (1967) Microscopic structures in kaolin subjected to direct shear: Geotechnique 17, 309–328.CrossRefGoogle Scholar
  21. Müller, G. (1967) Methods in Sedimentary Petrology, Part 1, pp. 100–101: Of Sedimentary Petrology. Hafner, New York.Google Scholar
  22. Oda, M. (1972a) Initial fabrics and their relations to mechanical properties of granular material: Soils and Foundations 12, 17–35.CrossRefGoogle Scholar
  23. Pettijohn, F. J. (1957) Sedimentary Rocks, pp. 72–74. Harper & Brothers, New York.Google Scholar
  24. Quigley, R. M. (1962) The engineering properties of illite related to fabric and pore water composition: National Research Council, Canada, Proc. 16, Canadian Soil Mech. Conf., Sept. 1962, pp. 21–42.Google Scholar
  25. Sides, G. and Barden, L. (1971) The microstructure of dispersed and flocculated sample of kaolinite, illite and montmorillonite: Can. Geotech. J. 8, 391–399.CrossRefGoogle Scholar
  26. Sienko, M. J. and Plane, R. A. (1961) Chemistry, 2d Edn. McGraw-Hill, New York.Google Scholar
  27. Sloane, R. and Nowatzki, E. (1967) Electron-optical study of failure changes accompanying shear in a kaolinite clay: Proc. 3rd Pan-American Conference on Soil Mechanics and Foundation Engineering, Venezuela, Vol. 1, pp. 215–225.Google Scholar
  28. Sowers, G. F., Robb, A. D., Mullis, C. H. and Glenn, A. J. (1957) The residual lateral pressures produced by compacting soils: 3rd Int. Conf. Soil Mech. Found. Engng, London, Vol. 1, pp. 243–247.Google Scholar
  29. Sowers, G. B. and Sowers, G. F. (1970) Introductory Soil Mechanics and Foundations, 556 pp. Macmillan, London.Google Scholar
  30. Terzaghi, K.(1931) The influence of elasticity and permeability on the swelling of two-phase systems: In Colloid Chemistry (Edited by Alexander, J.) Vol. 3, pp. 65–88. Chemical Catalog Co., New York.Google Scholar
  31. Terzaghi, K. (1943) Theoretical Soil Mechanics. Wiley, New York.CrossRefGoogle Scholar
  32. Terzaghi, K. (1956) Discussion on physico-chemical analysis of the compressibility of pure clays: Geotechnique 6.Google Scholar
  33. Terzaghi, K. and Peck, R. B. (1967) Soil Mechanics in Engineering Practice. Wiley, New York.Google Scholar
  34. Verhoogen, J., Turner, F. J., Weiss, L. E., Warhaftig, C. and Fyfe, W. S. (1970) The Earth, 748 pp. Holt Rinehart & Winston, New York.Google Scholar
  35. Underwood, E. E. (1970) Quantitative Stereology, 274 pp. Addison-Wesly, Reading, Mass.Google Scholar
  36. Windisch, S. J. and Soulié, M. (1970) Technique for study of granular materials: Proc. Am. Soc. Civ. Engrs. 96, (SM4) 1113–1126.Google Scholar
  37. Youd, T. L. (1970) Densification and shear of sand during vibration: Proc, Am. Soc. Civ. Engrs. Vol. 96 J. Soil Mech. Found. Div., 863–880.Google Scholar

Copyright information

© Clay Minerals Society 1974

Authors and Affiliations

  • Arshud Mahmood
    • 1
  • James K. Mitchell
    • 2
  1. 1.Woodward-McNeil & AssociatesLos AngelesUSA
  2. 2.Department of Civil EngineeringUniversity of CaliforniaBerkeleyUSA

Personalised recommendations