On unified characterization of wave velocity of sand: A focus on effect of particle shape

This technical note investigates the wave velocities of sand with different particle shape. The grain shape was evaluated by three shape descriptors, including the sphericity (S), aspect ratio (AR) and roundness (R). It was established that under similar conditions in terms of the packing density and the stress level, the shear and compression wave velocities decrease with the particle roundness. This trend can be predicted using the con-ventional empirical method. Yet, it needs a significant number of fitting parameters, thus hindering the appli-cation of the conventional method in the real problems. To address this concern, a better method was proposed to estimate the wave velocities by introducing the state parameter in the framework of critical state soil mechanics. It is shown that the new method allows a unified characterization of wave velocity in sand, while the combi-nations of shape descriptors are no longer used in the prediction. The predictive performance of the proposed method was further confirmed by the experiment results of sand with rotund particle shape from the literature.