Throughout this paper, the compressibility of granular soils is investigated by considering different loading modes. In particular, the difference in the response of the soil along an oedometric loading path, according to the nature of the axial loading, is explored. It is shown that the application of a boundary axial loading gives rise to a more pronounced nonlinear responsewith more important settlements than what is observed with a volume (downward hydraulic flow) loading. A theoretical approach is developed and the predicted results are confronted to experimental results obtained from an original apparatus allowing both volume and boundary loadings be applied. A satisfying agreement is obtained, validating the theoretical model proposed.