Basic Study for Crushing of Frozen Soil by Underwater Shock Wave

The final aim of study is confirm a new technique that can crush frozen soil and/or ice on the farm by underwater shock wave generated underwater explosion of explosive. In the cold region, for example, North Japan, Russia, Norway, and Sweden, etc., this technique can makes carry out early sowing and having large harvest. Especially, in Hokkaido prefecture Japan, if sowing is carried out in April, we may be expected to have a 150% of harvest of ordinary season due to the total of the sunshine hours. At first, we carried out experiments, which use detonating cord and ice block for the case of shock wave that collides aslant to ice. We obtained result that strength of the ice strongly depends on existence of bubble in the ice. So, we carried out experiments, which use explosive and ice block for the case of shock wave that collides verticality to ice. And, as the first step of pressure measurement, we experimented using the plate device that can detect shock wave. The process of breaking of ice was observed by using of the high-speed camera.