Internal Explosions in Embedded Concrete Pipes

Abstract

Blast tests on a full-scale concrete pipe embedded in soft soil were carried out to evaluate the behavior of the soil-structure system under the internal detonation of high-energy solid explosives. Two different stages were considered: the former focused on the detonation of a low entity charge within the pipe to maintain the concrete in the elastic regime and the latter concerned with adopting larger quantities of explosive to produce cracking and failure of the structure. Cylindrical charges ranging from few grams to hundreds of grams of a high-energy solid explosive were investigated and different tests were performed for each quantity by inserting the explosive charge in a cardboard cylinder hanged up in the middle of the pipe central segment by means of three thin plastic wires. The following quantities were measured in different sections along the pipe: side-on and reflected pressure-time histories at the inner surface of the structure, pipe radial acceleration, peak particle acceleration of the surrounding soil by means of accelerometers placed at different distances and depths from the section where the explosion occurred. The experimental results obtained during the performed blast tests are thus analyzed to understand the soil-structure system behavior under such fast transient dynamic phenomena.