Comment on: “Influence of inter-granular void ratio on monotonic and cyclic undrained shear response of sandy soils” by M. Belkhatir, A. Arab, H. Missoum, T. Schanz [C. R. Mecanique 338 (2010) 290–303]

The authors should be commended for their interesting experimental work on sandy soils presented in Belkhatir et al. (2010) [1]. They used the inter-granular void ratio, es, to interpret the experimental results and developed some useful correlations with es. However, the Note fails to address the further development of es over a decade to a more generalized form of equivalent granular void ratio, e⁎. This comment aims at adding missing literature on e⁎ and presents a re-interpretation of the experimental data based on e⁎. The advantages of using e⁎ over es are significant and explained in subsequent sections.