Once the ballast is placed, the Tunnel would be stable with the 8’ of Flowable fill.
If the Flowable fill is placed, it would be necessary to have 8' of Flowable fill + 2' of soil fill. Otherwise, it would be necessary to have 14 'of soil fill.
The Parallel Thimble Shoal Tunnel will form part of the parallel Chesapeake Bay Bridge-Tunnel Crossing, which connects Virginia Beach with Northampton County, VA. The new tunnel will carry two lanes of traffic southbound, while the existing parallel tunnel will be converted from bidirectional flow to one directional two lanes northbound flow.
The tunnel will have a length of approximatively 1.2 miles (1.9 km), a finished internal diameter of 39 feet (11.88 m) and will be excavated by using an EPB machine with an excavation diameter of 43.5 feet (13.2 m) designed to cope with an external water pressure of up to 5.5 bar.
Chesapeake Tunnel Joint Venture (CTJV) have asked AZIERTA for a Buoyancy calculation report for the new Tunnel. The client was looking for options to carry out the construction more efficiently, and needed to know the Buoyancy of the Tunnel itself to confirm viable options.
