McCrossin Foundations was subcontracted to install the drill and install the soldier piles for the support of excavation system required for the modifications of the tunnel required by The National Gateway project.
The diameter of the hole required for the soldier beams was 24-inch diameter and were drilled to depths up to 50 feet and including a rock socket up to 30 feet. The caisson shafts were drilled primarily through fills and weathered shale in the soil portion and hard to very hard sandstone and limestone bedrock, due to the underlying materials and existing site conditions some shafts required temporary casing during installation.
The tunnel is located along the Casselman River in Somerset County. The tunnel was built around 1884 and has an elevation of approximately 1,690 feet. It is a single track tunnel with a length of 1,856 feet and a grade of 0.79% falling to the west. A second track takes the low grade around the hillside. The tunnel has masonry/cut stone walls and brick arch, and the portal structures are masonry/cut stone. The tunnel has curves at both portals but is tangent through most of the tunnel.
The modifications to the tunnel include increasing the vertical clearance, relining the exposed bedrock, improvement and protection of the communication and utilities within the tunnel and the reprofiling of the track.
Job Name: Brook Tunnel Modifications
Job Location: Lower Turkeyfoot, Pennsylvania
Job Type: Soldier Beam Retaining Wall
Start Date: May 2013
Completion Date: May 2013