Impact assessment of unexploded ordanance disposal at the seafloor and the construction of aggressive environmental load reduction techniques

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K12393
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64020:Environmental load reduction and remediation-related
• Research Institution: Okinawa National College of Technology
• Principal Investigator: HIGA Yoshikazu 沖縄工業高等専門学校, 機械システム工学科, 教授 (20335368)
• Co-Investigator(Kenkyū-buntansha): 井山 裕文 熊本高等専門学校, 生産システム工学系MIグループ, 教授 (40300660)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 海中不発弾処理 / 数値シミュレーション / 避難海域 / 可視化水槽 / 水中衝撃波 / 一次飛散物

Outline of Final Research Achievements

This study investigated the environmental impact assessment of underwater unexploded ordnance disposal from the perspectives of experimental mechanics and computational mechanics. The results of the investigation during the study period are as follows:1)The propagation behavior of underwater shock waves and the behavior of fragments such as shells, explosives, and soil were revealed in response to the conditions of UXO detonation (explosive amounts, seabed soil and processing water depth, etc.). 2)A small visualization tank that can control the internal pressure of the container was designed and manufactured, making it possible to directly observe the propagation of underwater shock waves in an environment that simulates the water depth and measure the pressure-time history. 3)Based on the above results, it was shown that it is possible to consider a method to reduce the evacuation area during underwater UXO detonation from the perspectives of experimental and computational mechanics.

Free Research Field

計算固体力学，マルチフィジックス

Academic Significance and Societal Importance of the Research Achievements

実験力学および計算力学的視点により海中での不発弾爆破処理問題を明らかにすることで，理論的根拠に基づき避難区域が設定され，さらに当該避難区域を積極的に縮小化できる可能性を検討するための方法論を明らかにした．避難海域内の活動を制限することに起因する経済活動の停止および損失を最小限に抑えることができることは極めて有用な知見となる．一方，金属・土壌動特性を律速する固体力学分野に爆発的な燃焼を記述した熱力学＋反応場と海水を律速する流体力学分野を含め，複層的かつ複雑に関連したマルチフィジックス現象を取り扱う問題であることから，学術的意義は極めて大きい．