Technical tasks for Tokyo Bay crossing

摘要

Anew 18km long TBM bored tunnel under Japan's Tokyo Bay is at the centre of a project by the Tokyo Electric Power Company to provide for more flexible and efficient supply of liquefied natural gas (LNG) to its thermal power stations along the east and west coasts of the bay (figure 1). Unlike the first trans-Tokyo Bay project for the 15km long bridge-tunnel highway (10km in tunnel and 5km on the bridge), the 3.44m o.d. (3m i.d.) gas pipeline tunnel has no intermediate man-made islands to allow for TBM breakthroughs and required that two soft ground machines start from either side of the bay, meet in the middle, after completing about 9km each, and execute an undersea connection.