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This study presented in this paper investigates the effects of particle gradation and relative density on the shear strength of compacted sand samples with different grain size characteristics. Samples representing poorly and well graded sand soils of different origins were considered and prepared in the laboratory at initial relative densities of 40, 70 and 90% and their shear strength was determined by direct shear method. The grain size analysis tests performed on the samples showed that the average (Dav) and mean (D50) grain size diameters are closely interrelated despite the differences in the soil gradation patterns. Sound linear relationships were developed between the soil minimum dry density (Dmin) and the above two grain size parameters. The effect of grain size on shear strength was investigated but no useful correlation was found between the parameters Dav and D50 and the peak shear strength of studied soils. The study results indicated that there is a linear relationship between peak shear strength (τ) and the relative density (Dr) such that the soil strength increases as the Dr value increases. However, the relationship between Dr and τ is dependent on the normal stress (σn) applied on soil samples during testing. The effect is more pronounced and the relationship between τ and Dr is more reliable for soil samples subjected to lower than to higher normal stresses. Furthermoresince the sand samples tested were unsaturated the influence of Dr on shear strength might have also been overshadowed by their initial matric suctions.


Soil particle gradation; relative density;shear strength;compaction;sandy soils

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. Das B.M, Principles of Geotechnical Engineering.

Cenage Learning, 2006.

. Hamidi, A., E. Azini and B. Masoudi, 2012. Impact

of gradation on the shear strength-dilation behavior

of well graded sand-gravel mixtures, Scientia Iranica, 19(3): 393-402.

. Ogbonnaya, I., S. Kyoji and F. Hiroshi, 2012. The effect of relative density and confining stress on shear properties of sand with varying grading,Geotechnical and Geological Engineering, 30(5): 1207-1229.

. Yasin, S.J.M. and A.M.M. Shafiullah, 2003. Effect

of particle characteristics on the strength and volume change behaviour of sand, Journal Of Civil Engineering, The Institute Of Engineers Bangladesh, 31(2).

. Sezer A., Selim A. and Goktepe B. A. (2011) “Relationship between shape characteristics and shear strength of sands” Soils and Foundations,Volume 51, No. 5, pp 857-871, Oct. 2011.

. Liu, C., J.B. Evett, 2005. Soils and Foundations, Pearson Printice-Hall.

. Kokusho, T., T. Hara and R. Hiraoka, 2004. Undrained shear strength of granular soils with different particle gradations, 13th World

Conference on Earthquake Engineering Vancouver, B.C., Paper No. 144. Wu [10]

. Patra, C. R., Civakurgan N. and Das B. M. (2010), “Relative density and median grain size correlation from laboratory compaction tests on granular soils”, Int. Journal of Geotechnical Engineering, Vol. 4, Issue 1, pp. 55-62.

. Wue T. H. (1957) “Relative density and shear strength of sands” ASCE J. Soil Mech. , Vol. 83, SM1, pp. 1161-1123.

. Esmat Z. A. K. and Fadhil A. I. (2016) “ Effect of

relative density on the matric suction and its contribution to shear strength of unsaturated sandy soils” Applied Research Journal, Vol. 2, Issue 4, pp.134-142.

. Hilf J. W., (1970) Foundation Engineering Handbook, 2nd Edition, Chapman and Hall, pp.249-316.

. BS 1377, 1990. Methods of Tests for Soils for Civil Engineering Purposes, BSI, London.

. ASTM Standard D-4253, Standard Method for Maximum Index Density and Unit weight of Soils using a Vibrating Table. ASTM International DOI:101520/D4253, 2006.

. ASTM Standard D-4254, Standard Method for Minimum Index Density and Calculation of Relative Density. ASTM International DOI:

/D4254, 2006.

. Farouk, L. Lamboj, J. Kos (2004) “Influence of Matric Suction on the Shear Strength Behaviour of Unsaturated Sand” Acta Polytechnica Vol. 44 No.4/2004


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