Estimating the Peak Indentation Force of the Edge Chipping of Rocks Using Single Point-Attack Pick

This article establishes a new model for estimating the peak indentation force of the edge chipping of rocks when using a conical or a pyramidal point-attack pick. The investigation points out that the existing formulation in the literature is based on an inappropriate stress assumption and equilibrium, and hence leads to incorrect cutting force estimations. The new model developed in this study is based on an analysis of the penetration force and energy dissipation using fracture mechanics, similarity of chip geometry, and edge chipping tests on four different rock materials. It is found that the peak indentation force and the depth of cut follow a power law, that the new model can reasonably estimate the experimental measurements, and that it provides useful information for the shape optimization of point-attack picks in mechanical excavation.