The paper presents the importance of particles shape of fine-grained non-cohesive soils in water permeability process and its role according to the Eurocode 7. Methods of determining the permeability coefficient based on empirical formulas recommended by the above norm as reliable tools were particularly analysed. In order to the methods evaluation, laboratory test of two fine-grained non-cohesive soil materials were conducted. Tested grounds were characterised by the same grain size distribution and extremely diverse particle shape characteristic. Permeability coefficient calculations verifying this approach based on the formulas most often used in practice were performed. The obtained results were compared with laboratory tests conducted on soil samples which had the same value of void ratio, as used in calculations. The results have shown that using empirical formulas as the methods of permeability coefficient calculation of non-cohesive soil, which is recommended by Eurocode 7, is not a reliable way to determine this parameter, due to insufficient approach or ignoring the soil microstructure factor.

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