Shield Tunnelling Association of Japan
The Shield Tunnelling Association of Japan was established in 1999, and its membership consists of 97 companies including leading general contractors, TBM and lining segment manufacturers. 14 proven and reliable shield tunnelling methods have been registered with the association to date, and the association is helping to apply these shield tunnelling methods to various projects and promoting widespread use of those methods.
The history of shield tunnelling methods in Japan
In 1939, shield tunnelling was used successfully for the first time to construct a circular railway tunnel. In the 1960s, shield tunnelling began to be used for various infrastructure projects in urban areas, and the open shield method had its heyday until the 1980s. The period from 1980 to 1990 saw a transition from open TBM to closed TBM such as earth pressure balance shield machines developed in Japan. At present, 98 percent of TBM machines used in Japan are closed type. During the peak period in the 1980s, as many as 300 contracts were awarded each year for shield tunnelling work, and marked progress was made in infrastructure development. Today, the number of shield tunnelling contracts awarded each year is around 70. However, with a variety of new shield tunnelling technologies developed such as the 14 shield tunnelling methods.
Recent advances in shield tunnelling research and development
A variety of technologies are being developed to promote the utilization of underground space in built-up urban areas. The recent enactment of a new law permitting the use of underground space at depths of more than 70 m below ground surface has accelerated the research and development of new shield tunnelling technologies, such as branching and enlargement.