Abstract: In this paper, we discussed the shear strength, stress-strain properties and dilatancy of cohesionless sand cobbles and rockfill materials, based on a large number of large scale triaxial compression tests in many engineering projects. The paper has shown some of variation rules in the behaviour of these materials, and presented that the shear strength of cohesionless sand cobbles is correspondent with or even better than that of rockfill materiale. Moreover, the paper discussed the influence of dilatancy on shear strength and poisson’s ratio. At last, the Duncan’s model and it’s model parameters have also been discussed.