Abstract
A series of field and laboratory tests of ram blow to confirm that the impact force and compaction of sandy ground are dependent on the ram momentum rather than the kinetic energy were carried out under a variety of ram masses from 1.25kg through 25t and of ram base area and drop height. The waveform of ram impact acceleration was predominantly dependent on the ram mass per unit area of the ram base, and the effect of drop height on the waveform was less as expected from previous laboratory tests. The maximum impact acceleration, maximum impact stress and the ram penetration of the ground were well interpreted by the proposed mathematical models.
