The Integration of the Morphological Aspects of Sand to It’s Shear Strength and Dilatancy Characteristics

The integration of geological and morphological features to the geotechnical characteristics of coarse grain soils can lead via statistical methods to determined correlations between strength and its physical properties. The shape and sizes of sand particles reflect the formation history of the grains where it results from the disintegration of rocks due to water, weather and glaciers. The particle interactions of sand due to shear deformation and also seismic reactions of different shape and sizes would result in various sedimentological macroscale behaviour. Clean sands are cohesionless (c = 0) but have a finite friction angle (Ø) and its shear strength is entirely dependent on the density, normal stress and interlocking particle structure. The latter is associated with the property of the angle of dilatancy (ψ) in particular with sands. Direct shear box testing was done on samples of well graded sand (SW) and poorly graded uniform sand (SPu_Kahang) from Kahang Malaysia and also (SPu_L.Buzzard) uniform Leighton Buzzard sand from the UK. The shapes of the sand particles were quantified using images obtained from a digital microscope. Ø_peak, Ø_cr and ψ are the highest for (SW) when compared with others. SPuL.Buzzard sands showed a significant decrease in the values with similar relative density (D_r). High normal stresses give very little variations in the angle of dilatancy (ψ) between the samples tested as compared to the lower normal stress that was used. This research contributes to furthering the understanding of the engineering behaviour of sand and also helps in predicting the occurrence of dilation based on sand morphology in dynamic soil structure interaction.