In this experimental study, behaviour of dry granular layers of monodisperse cylindrical particles (8x1 mm) under uniaxial compression was studied. The layer compressibility and PSD were evaluated. The effect of several parameters was investigated: piston speed, layer size (diameter and height), applied pressure. Two modes of compression were tested: non-recurring and recurring. In the former mode, after the compression, the particles were taken out of the measuring cell for granulometry. In the latter mode, after granulometry, the particles returned to the cell for the next run with the same pressure. It was found that neither the piston speed nor the layer size were relevant, within our experimental range. The resulting compressibility and PSD were affected mainly by the normal pressure and the way it was applied. In the non-recurring mode, with increasing pressure, PSD moves toward smaller sizes of broken particles always leaving some initial particles intact. In the recurring mode, the pressure had more destructive effect, resulting in larger particle fragmentation. The reason is seen in the particle re-arrangement between the successive tests.