耐火トンネルのニーズ拡大と当社の取り組み
危険物積載車両のトンネル通行規制緩和や欧州の大規模トンネル火災事故等を背景に、より高い耐火性能を持つトンネルのニーズが拡大している。現在、日本ではトンネルの耐火性能は物件毎に実験により検証されている。当社には、秋田中央道路シールドトンネルに提案した耐火工の性能を実大サイズの試験体によるトンネル火災を想定した急速加熱実験により検証し、実施適用した実績がある。また、将来的な技術として有機繊維を混入して爆裂を抑制した耐火セグメントの製造と品質管理方法を提案し、実大セグメントの製造と耐火試験を通して、その有効性と優れた耐火性能を検証した。
キーワード： トンネル火災，耐火性能，急速加熱実験，耐火セグメント，耐火被覆
＊１ 技術センター建築技術研究所防災研究室
＊２ 技術センター土木技術研究所土木構工法研究室
＊３ 土木本部土木技術部
＊４ 土木本部土木設計部
Structural Fire Resistance of Road Tunnels: Research Needs and Taisei's Commitments
The relaxation of traffic regulations for combustible substances in Japan, catastrophic underground fires in Europe, and other recent developments have emphasized the importance of structural fire resistance for road tunnel construction in Japan. The fire performance of each road tunnel structure must be investigated and verified to ensure that it meets or exceeds the design specification. This paper summarizes Taisei's commitments in the field over the past few years.A case in point is the Akita Chuo Doro shield tunnel being constructed in the city of Akita, Japan. The tunnel is scheduled for completion in March 2007. For the project, Taisei developed a board-based fire protection system. The system was fire-tested on a full-scale shield segment model and verified using the German RABT fire curve. The system was also tested for durability, and approved for use in the tunnel.Taisei is also developing fire resistant tunnel segments for future projects. These segments don't provide fire protection, but because the concrete mix contains a type of polymeric fiber, they minimize the risk of explosive spalling during fires at the concrete cover. Full-size segments have been fabricated for fire testing as well as for monitoring the effectiveness of the proposed fabrication quality control procedures. Their fire resistance has been verified using a one-hour RABT curve.
Keywords: tunnel fire, fire resistance, rapid heating test, fire resistant tunnel segment, fireproof
*1 Disaster Prevention Research Section, Building Research Institute, Technology Center
*2 Civil Structure and Material Research Section, Civil Engineering Research Institute, Technology Center
*3 Civil Engineering Technology Promotion Department, Civil Engineering Division
*4 Design Department, Civil Engineering Division