Deformation Characteristics of Granular Materials in Cyclic One-Dimensional Loading Tests

In order to study deformation characteristics of geomaterials under simulated traffic loading conditions, a series of cyclic one-dimensional loading tests was conducted on compacted specimens with varied heights, which were made from four types of granular materials consisting of particles with a mean diameter in the range of 2.2 to 5.8 mm. By assuming that the top and bottom ends of the specimen were affected by the bedding error, it was attempted to estimate the residual strain after cyclic loading and the constrained modulus during cyclic loading of the tested specimens, which are free from the effects of bedding error. As a result, the residual strains of the tested materials were on the order of 0.1 %, while much higher residual strains were estimated for the layers affected by the bedding error. In addition, the estimated values of the constrained modulus were much larger than their nominal values that were evaluated in a conventional manner. With one type of the tested material, however, reasonable estimation could not be made, suggesting a limitation of the simplified assumption. The estimated values of the residual strain of the normal layer and the constrained moduli were consistent with the results from relevant triaxial tests.