From the ACEC-VA website: “Brierley Associates pushed the limits by using a new method to install vehicular box tunnels under the railroad crossing on the West Campus of Liberty University. The underground passage was needed to improve safety and traffic flow at the railroad crossing. The challenge was to protect the embankment opposite the box tunnel launch side.
“Brierley’s solution: pull don’t push. Conventional pushing or jacking the box tunnels into place posed the possibility of ‘blowing-out’ the opposite side of the rail embankment during tunnel advancement. Brierley Associates built a reaction wall on the opposite side of the tunnel launch pad and pulled the box tunnels into place, a technique that had not previously been used in North America. It significantly reduced costs associated with conventional jacking and confined the embankment during advancement of the box tunnel, alleviating ‘blowout’ concerns, loss of ground and track settlement. The $6.9 million project was completed under budget and opened up the Liberty University campus to future growth.”
The project consisted of jacking two cast-in-place concrete tunnel sections, both 32 ft wide x 20 ft high x 130 ft long, into an embankment under active Northern Southern Railroad Tracks to be used as a vehicular tunnel for access to Liberty University. Southland Contracting was the tunnel contractor.
The tunnel replaces an at-grade crossing of a rail line, enhancing safety and efficiency.