The combined effect of bonding and particle size variables on the undrained behavior of sandy soil

Naturally bonded sands are of various gradings and behave differently from unbonded sandy soils. An understanding of the combined effect of bonding and the variation of particle size on their engineering behavior and mechanical properties is required for a better geotechnical design. In this study, the coupled influence of bonding and particle size of sand-kaolin soil mixtures was studied under different confining pressures in triaxial consolidated undrained conditions. From the results it was found that for bonded samples, the peak strength and cohesion intercept vary in the same way as the mean particle size and coefficient of uniformity, while the trend was altered for unbonded materials. However, the angle of internal friction increases in the presence of bonding and decreases as the mean particle size increases under both states. The said coupled influence was found to be more pronounced at low confining stress. The bonded soil of bigger particle size is less ductile than that of smaller particle size, particularly for the test conducted at low confining pressure.