Kajima, MHI and Kawasaki to Jointly Develop Shield Tunneling Technology

Feb. 22, 2006

 Tokyo, February 22, 2006 – Kajima Corporation, Mitsubishi Heavy Industries, Ltd. (MHI) and Kawasaki Heavy Industries, Ltd. announced today that they have agreed to jointly develop shield tunneling technologies that will enable the expansion of tunnel width and merging/diverging of multiple tunnels without using open-cut construction, and a new shield machine.

 The conventional cut-and-cover method has been used to build junctions for utility tunnels, to expand tunnel widths for emergency parking space and rampways, and to merge/diverge multiple road tunnels and railroads. However, as more metropolitan shield tunnels are being built deeper in the ground, and are longer and larger in diameter, a method to expand tunnels and merge/diverge multiple tunnels must be devised that does not cut the land open. This would solve the difficulty of obtaining land and also reduce environmental impact. These factors prompted the three companies to launch a joint R&D scheme and focus on advancing such trenchless technology in a more comprehensive manner.

 Under the scheme, Kajima will contribute its shield tunnel construction technology. MHI and Kawasaki will leverage their shield machine technologies to enhance the VASARA method (VAriable width SAving space RApid construction) used for building emergency parking space within road tunnels and the D-Shape shield method used for building merging/diverging sections of road tunnels such as rampways. The engineering divisions of the three companies plan to conduct a large-scale verification test of the new shield machine in the fiscal year ending March 31, 2007.