ABSTRACT
The mechanical properties of solid-like granular materials are well known to depend on the internal structure of the packing. Classically, one distinguishes between the behavior of dense and loose materials (Wood 1990; Mitchell 1993). However, some results – see e.g. (Benahmed et al. 2004) – also indicate that other factors than the sole packing fraction (or void index) also determine the quasistatic response to applied load variations. In numerical simulations, it is a common practice to remove friction in the assembling stage in order to prepare dense samples (Makse et al. 1999; Thornton 2000). It is not guaranteed that the correct initial state, as obtained in laboratory experiments, is reproduced. Elastic properties, or sound wave velocities, are now commonly measured in soil mechanics (Chen et al. 1988; Hicher 1996) and condensed matter physics (Jia et al. 1999) laboratories. Their evaluation in numerical calculations can allow for comparisons with experiments.
