A note on the penetration of a rigid wedge into a nonisotropic brittle material

Abstract

In the present note an existing wedge penetration theory for isotropic brittle materials is extended to explain some `bedding plane' effects observed in a series of experiments on Indiana limestone.The general features of the theory presented by Paul and Sikarskie [Trans. AIME 232, 372-383 (1965)] are kept here and in order to extend the analysis to the anisotropic case Jaeger's modification of the Coulomb-Mohr failure criteria is used.Two specific cases of bedding plane orientation are considered, namely those in which the bedding planes are parallel and perpendicular to the direction of penetration.The theory presented gives an insight into the anisotropic effects and predicts, in reasonable agreement with the experimental results, the observed differences in specific energies for the different penetration directions.