  The finite element method and dimensional analysis have been applied in the
present paper to study a hydraulic impact, which is utilized in a non-explosive
rock breaking technology in mining industry. The impact process of a high speed
piston on liquid water, previously introduced in a borehole drilled in rock, is
numerically simulated. The research is focused on the influences of all the
parameters involved in the technology on the largest principal stress in the
rock, which is considered as one of the key factors to break the rock. Our
detailed parametric investigation reveals that the variation of the isotropic
rock material properties, especially its density, has no significant influence
on the largest principal stress. The influences of the depth of the hole and
the depth of the water column are also very small. On the other hand,
increasing the initial kinetic energy of the piston can dramatically increase
the largest principal stress and the best way to increase the initial kinetic
energy of the piston is to increase its initial velocity. Results from the
current dimensional analysis can be applied to optimize this non-explosive rock
breaking technology.
