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Laboratory test programs on gravel are rare due to the maximum grain size of the material. In this paper an experimental program with triaxial tests under cyclic loading and oedometric tests on highly compacted gravel specimens, representative for bridge backfills materials, is summarized. It is used to calibrate a hypoplastic constitutive model, which includes an extension for intergranular strain to account for the cyclic loading behaviour. So far calibrated parameter sets of this soil model are scarce in literature, especially for coarse grained materials. The calibrated parameter set can be used in numerical studies, e. g. on the cyclic soil structure interaction of integral railway bridges.

The present study is devoted to the investigation of the dilatancy behaviour of a fine sand based on hollow cylinder tests. Medium and dense samples were tested at a constant average γ = 1, 2, 3 and 4%. Dilatancy curves along with shear wave velocity measurements to investigate the influence of the shear strain amplitude γampl in the shear modulus degradation curve are presented and discussed. The measured stress and strain paths were used to compare the performance of four advanced constitutive models especially in describing the dilatancy behaviour of sand. From the perspective of their constitutive equations, the differences between the simulations with various material models are examined. It may be concluded that all four models allow a proper prediction of torsional shear tests as long as a proper calibration of the material parameters is secured.