Selection of tunnel and shaft construction methods is one the most influential items on any cost and period of power cable project. In TEPCO's projects, several high technical construction methods have been adapted such as long span driving shield, mechanical shield docking, dual shields, pipe jacking under high groundwater pressure and new type tunnel lining etc. We have reduced construction costs by applying those methods. Therefore we possess high technologies for selection of the most suitable construction methods. It is possible for us to draft the most suitable tunnel and shaft construction methods from among all methods considering cost, period and environment.

Dual Shield Method

Contents of selection of tunnel and shaft construction methods are as follows.

• Options of Applicable Method

• Conditions for primary selection of possible options are as follows.
  • Surrounding conditions : Road and residence conditions, ground condition, existing objects etc.
  • Specifications : Cross section shape, Dimensions, Length, period, Plan and longitudinal alignment etc.

• Typical construction methods are as follows.
  • Tunnel : Shield, Open-cut, NATM and Pipe Jacking etc.
  • Shaft : Steel (sheet) pile, Caisson Diaphragm wall and etc.
• Additional Countermeasures
• Finishing Selection of the Most Suitable Method

We evaluate all options about cost, period and reliability. Then we select the most reasonable method.