Kakegawa No. 1 Tunnel, Japan

Bekaert fiber concrete reinforcement Kakegawa tunnel Japan

Project type:
Road tunnel 

Final Tunnel Lining

> Owner: Dai-Ni-Tomei, Japan
> Contractor: Maeda 

The main line of National Route 1 is the second longest land-based route on the island of Honshū, Japan. Along the route, near the city of Kakegawa, runs a 600 meter long twin road tunnel. 

Bekaert provided Dramix® steel fibers for the final lining of this tunnel as well as an automatic dosing machine to control the addition of the steel fibers to the concrete mix as and to measure the final steel fiber content of the wet concrete mix.

The challenge

The materials used for the design needed to comply to NATM principles. Designs based on these principles typically require a high stability of the permanent support lining. As the tunnel is part of a major intersection of the National Route 1, execution time was limited.  

The solution

A cast-in-place concrete lining of 500mm (20 in) thick was placed over a waterproof membrane. The concrete mix of the lining uses 40kg/m3 (66 lb/yd3) of Dramix® steel fibers for structural and thermal stability. The construction progressed at a rate of 160 m³ of SFRC placed in three 8 hour days for each 10.5 m (35 ft.) run of tunnel. 

Bekaert fiber concrete reinforcement Kakegawa tunnel Japan

Automatic fiber dosing system by Bekaert