Evaluation of the unconfined compressive strength of rocks using nail guns

The penetration depth is one of the major index parameters for indirect determination of the unconfined compressive strength (UCS) of rock. That is, the weaker the rock, the deeper the nail penetration should be, and vice versa. However, the penetration depth depends on the strength of material, the impact energy and nail diameters of nail guns. In order for an empirical equation relating the penetration depth to the UCS to be widely used, the equation should be related to all varieties of gasnailers.