Gravity‐Scaled Tests on Blast‐Induced Soil‐Structure Interaction

Abstract

Centrifuge model tests were conducted on models of flexible shallow tunnels in dry sand subject to blast loading from nearby highenergy explosives. Experiments were conducted with varying centrifugal accelerations (from 1 g to 97 g on 2.5‐5‐cm‐diameter model tunnels made of thin brass and aluminum sheet. Buried, 1/2‐g and 1/16‐g pentaerythritol tetranitrate (PETN) explosive charges were detonated at a distance of 0‐2 diameters from the tunnels during centrifugation. It appears that for flexible tunnels which are exposed or nearly exposed by the crater, significant damage to the tunnel occurs during crater excavation. The intense flow which occurs in the soil near the crater appears to be the major cause of distortion of the tunnel and the shock wave itself is often less significant. The distance from the tunnel to the crater appears to be a more significant factor than the distance from the tunnel to the charge in causing damage to flexible tunnels. Since gravity influences the cratering process, and consequently influences the soilstructure interaction, it is important to conduct scale‐model tests of this type of event on a centrifuge. The centrifuge scaling laws were verified by conducting modeling of models tests using 1/97‐ and 1/48.5‐scale tests. Cratering efficiency is also compared to that measured by other researchers with reasonable agreement.