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Science and Technology of Energetic Materials

Vol.63, No.6 (2002)

Research paper

Relationship of fragmentation of cylindrical rock specimen and incident underwater shock wave
Woo-Jin Jung, Yuji Ogata, Shiro Kubota, Hideki Shimada, and Kikuo Matsui
p.404-409

Abstract

This paper presents a new technique to estimate the behavior of the dynamic fracture of rock under explosive loading. The explosive materialis used as the explosion source, and a pipe filled with water is arranged between the explosive and the cylindrical rock specimen. After the explosion, the detonation wave interacts with water and the under water shock wave is generated in the pipe. Because the under water shock wave attenuates with its propagation, the impact strength of the shock wave into the rock specimen can be easily adjusted by changing the length of the pipe. The free surface velocity at the end of the rock specimen and the position of cracks on the rock surface are observed by using a laser vibration meter and high - speed camera, respectively. The results of the fracture test for Kimachi sandstone are discussed. Moreover, the numerical simulation was carried out to understand the behavior of underwater shock wave generated by underwater explosion of the explosive. The 2D hydrodynamic code based on ALE finite difference scheme was employed. In the case of the fracture test with 50 mm water pipe, the incident underwater shock wave into the cylindrical rock specimen has an irregular pressure distribution near the shock front.

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