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Home > R & D and Technologies > Shield Tunneling Methods > DOT Shield
Daiho started development of this Method for the purpose of effective use of underground space in 1987 and completed horizontal and vertical double circular face machines in the next year through proof tests at site. Principle of face stabilization by muddy soil is same as DK shield Method.

Machine for Horizontal Double
Circular Type Proof Test
(F 2.50m x W 4.185m)
Machine for Vetical Double
Circular Type Proof Test
(F 2.50m x W 4.185m)
Loading Test of Segment Ring
1. Technical Advantages;
1) Free combination of circular cut faces depending upon underground conditions and working environment.
2) Smaller cut face enabling to reduce unnecessary cut face area compared with independent 2 tunnels.
3) Environmentally friendly and cost & energy saving due to reduction of cutting face area which minimize volume of muck.
Horizontal Configuration Vertical Configuration
3 or 2 circular cutters can be combined and fixed into one machine.
2. Real Apprication to Projects;
New MRT System of Hiroshima
(F 6.09m x W10.69m)
(Completed in 1994)
Narashino Kikuta River Trunk Sewer Line No.2
(F 4.45m x W 7.65m)
(Completed in 1994)
Subway Line No. 4 of Nagoya City
(F 6.52m x W11.12m)
(Completed in 2004)
Shanghai Subway M8 Line
People's Republic of China
(F 6.52m x W11.12m)
(Completed in 2004)