Simple Shear Behavior of Calcareous and Quartz Sands

The monotonic and cyclic simple shear behavior of several loose skeletal calcareous sands is investigated and compared to that of common Nevada and Ottawa quartz sands in order to draw contrasts between these types of materials and to develop stiffness and modulus degradation curves for quasi-nonlinear ground response analysis. Mobilized frictional resistance and cyclic strength are generally higher for the calcareous sands, whereas shear modulus and damping are larger for quartz sand at strain levels between 0.05 and 1%. Degradation properties do not appear to be very sensitive to the initial cyclic stress ratio. Differences in behavior between the calcareous and quartz sands are presumably due to contrasts in grain geometry, hardness, gradation and the amount of intraparticle voids.