Measurement of explosively induced movement and spalling of granite model blocks

Charges of high explosives have been buried (countersunk) in granite blocks and detonated. This article describes the measurement and evaluation of the shock wave propagating through the granite blocks. It also demonstrates how the shock wave data can be used to improve computer simulations of graniteʹs behaviour. The overall goal has been to investigate how granite withstands penetrating weapons, that first penetrate the ground and then detonates within the created cavity. Several variables have been investigated. It is shown that water content of the granite can increase the shock wave amplitude with up to a factor 2, and a crack in the granite often attenuates the shock wave amplitude with a factor 4 or more. Also, the granite block thickness needed to prevent internal crack formation has been investigated.