Small Scale Tests on Mitigation Effects of Water in a Model of the KLOTZ Club Tunnel in Alvdalen

Abstract : The effects of water in close contact with detonating high explosives have been studied in several test series and it has been determined that water has a mitigation effect on the blast wave from an explosion. Both maximum overpressure and impulse density will be reduced. The effective charge size can be reduced with more than 50%, possibly as much as 80%. This means that possible equivalence factor is 0.2 (amount of high explosive with/without water giving the same effects). It has been suggested as a very interesting concept to store ammunition or high explosive together with containers of water to reduce the effects of accidental explosions. A full scale test with real ammunition and water used for mitigation is planned to take place in The KLOTZ Club tunnel in Aelvdalen in fall 1996. For planning and preparation purpose of the full scale test a comprehensive test series in a small scale model of the tunnel has been performed. Different locations of water and charge to water ratio have been studied. Pressure time histories have been recorded inside and outside the tunnel. Some simple experiments were also made to compare the effects of debris throw, with and without water mitigation.