Development of an Unmanned Prelining Machine Using the Pre-Arch Shell Support (PASS) Method

Since the NATM method was introduced to Japan some 15 years ago, the technologies and techniques involving tunnelling and the construction of underground caverns have seen some noticeable developments, and their applications have been extended not only to mountain areas, but also, more recently, to urban areas. However, the application of the NATM method for construction in urban areas has experienced various difficulties because it was initially developed for application in the construction of tunnels in mountainous areas. To eliminate this handicap, we have developed the PASS method, which allows for the construction of a concrete arch ahead of the facing, as well as for an unmanned machine to execute that work.