Tunnel boring machine arrives for Hampton Roads expansion project
The Hampton Roads Bridge-Tunnel (HRBT) Expansion Project held an arrival ceremony to celebrate the arrival of “Mary the Tunnel Boring Machine.”
The Hampton Roads Bridge-Tunnel (HRBT) Expansion Project reached a significant milestone with the arrival the Herrenknect tunnel boring machine (TBM) that will be used to construct new twin two-lane tunnels that will accommodate four lanes of traffic for a total of eight lanes of capacity across the water and will be constructed as bored tunnels at Hampton Roads, VA.
An arrival ceremony for the TBM, named Mary, took place on Tuesday, Dec. 14, 2021 at Portsmouth Marine Terminal, WAVY.com reported.State and regional officials were present including Virginia Department of Transportation (VDOT) Commissioner, Stephen Brich and VDOT HRBT Expansion Project Director, Jim Utterback.
Measuring 131 m (430 ft) long and 14 m (46 ft) in diameter, Mary was named after Mary Winston Jackson. The name was chosen by Hampton Roads middle school students.
The HRBT expansion project aims to alleviate backups by adding two new tunnels and four additional lanes. The tunnels will be constructed using the bored tunnel approach, the first time that method has been used by VDOT. It is the largest highway project in Virginia history.
In May, the machine was assembled and passed its factory acceptance test. It was disassembled and shipped from Germany to Virginia for its debut at an arrival ceremony.
The tunnel boring process will take about a year. It will start on the South Island and move toward the North Island at a rate of up to 15 m/d (50 ftpd). After reaching the North Island, it will take about four months to turn the machine around.
After being turned around, Mary will spend another year digging a parallel tunnel back to the south Island.
Each tunnel will be able 2,438 m (8,000 ft) long. The deepest part of the new tunnels will be about 150 feet underwater. The new tunnels will be about 15 m (50 ft) deeper than the current HRBT tunnels.
“Today’s arrival of Mary is a major milestone in this generational project, the expansion of the HRBT,” said VDOT Commissioner Stephen Brich in a VDOT news release after the ceremony. “Today, we are closer than ever to offering increased options, capacity and reliability for our region, and with the latest tunneling technology, Mary will have little impact to the environment and to the waterway’s Navy, marine and commercial boat traffic while she’s drilling.”