According to Roy, the toughest task was creating a tunnel which began beneath the historical Russian Wharf Building and extending it under the Fort Point Channel to the new World Trade Center Station. These tunneling technologies are well established in Europe and have been used for various other major projects throughout the United States. With the NATM, the ground is frozen ensuring its predictability while the work is done. The process gives more control of the ground when removing obstacles with less risk of sinkholes and uncontrolled ground settlement during excavation. Although this tunneling technology is relatively new to this country, Roy feels that NATM will become more popular in areas where ground conditions warrant.
Ground freezing is a temporary condition that leaves the area in the same condition as it was found.
Although certain risks are inevitable with any tunneling job, we are confident that with careful planning, the NATM method on this project can minimize these risks.