Cemetery Brook Drain Tunnel Project Photos
Welcome to the photos page of the CBDT project website! Provided below are current photos showing the status of each of the major project locations, including the TBM Launch Zone and each of the Drop Shafts. Located at the bottom of this webpage is "Beyond the Site" with status photos or images associated with design, planning, major project milestones and various construction aspects of the tunnel project.
Project Site Status Photos
Site 1 - Launch Zone (Queen City Ave. Bridge)
Connection operations for the Tunnel Boring Machine (TBM) a.k.a. "Granite Janet" within the launch zone. The TBM comes in several different pieces that will be connected within the launch site before it begins drilling. There are several support utilities needed for the TBM to operate, including power cables, air supply piping, ventialtion systems and slurry piping. This portion of the TBM is where the tunnel liner segments will be installed. The two pipes in the middle of this section will be connected to the oniste slurry plant to send drilling fluid to the front of the machine and return mined material back to the launch site.
Site 2 - Drop Shaft (DS) - 1 (Queen City Ave.)
As controlled blasting within Drop Shaft 1 is completed, the exposed rock is supported with anchors and gunite (sprayed cement). Once the holes are drilled to a 5 foot depth, material is placed to "blast" or break up the rock. Once a controlled blast is complete, excavation of rock and soil is completed, followed by installation of steel bracing as Drop Shaft 1 gets deeper. Steel braces and rock supports (gunite material) will help hold the soil and rock in place to maintain a safe working space within the support of excavation (SOE) walls.
Site 3 - Drop Shaft (DS) - 2 (Union Street)
Placement of concrete to form the tunnel bulkhead at the far end of the "adit" at DS-2. An adit is a short tunnel constructed horizontally through the rock, which will connect the completed Drop Shaft to the completed Tunnel. This adit is constructed by blasting and removing rock at the bottom of the drop shaft, roughly 70 feet below ground level. Concrete was added at the bottom to level the floor and concrete will be placed on the walls of the adit. This section of wall is at the end of the adit and will be drilled through by the TBM.
Site 4 - Drop Shaft (DS) - 3 (Beech Street)
Drilling of ports and installation of grout material at the Drop Shaft 3 ground improvement area using "jet grouting" technology. Ground improvements are needed at several locations along the tunnel path. The grout material is injected into the ground 60-80 feet below the surface using hundreds of small drilled holes. High pressures are used to inject the grout into soft soils to "harden" the soft ground. Eventually, the TBM will drill through this hardened ground and the improved soil will be used to control groundwater and provide safe locations for the TBM to be maintained.
Site 5 - Drop Shaft (DS) - 4 (Wilson Street)
Pre-drilling operation to provide clearance for the installation of steel sheet piles. These piles are needed for support of excavation (SOE) installation to hold the soil back within Drop Shaft 4 excavation.
Site 6 - Drop Shaft (DS) - 5 (Taylor Street)
Site access road to future location of Drop Shaft 5.
Site 7 - Drop Shaft (DS) - 6 (Massabesic Street)
Installation of a tunnel vent shaft located across from the Drop Shaft 6 location on Massabesic Street. This vent is drilled using a large diameter drill bit connected to the drill rig. Once the drilling is complete, soils are removed and a pipe is installed to make a permanent vent. These vents are used throughout the length of the tunnel to remove air as the tunnel fills with water during rain events.
Site 8 - Drop Shaft (DS) - 7 (Mammoth Road)
Installation of a water tap located in Mammoth Road for water supply at future location of Drop Shaft 7.
Site 9 - Consolidation Drainage Piping (Union, S. Willow, Cilley)
Placement of the a drainage manhole within soil support systems (SOEs). This manhole is part of the new 60-inch drainage pipe being installed near Union, Shasta and Willow Streets. Utilities such as gas, drinking water and sewer pipe have to be relocated and adjusted to fit the new drainage pipe in the ground. Manholes are used where the new drain pipe will change in direction or depth.
Site 10 - Supplemental Vent Shaft (SV) - 2 (Maple & Silver)
Preparation and delivery of equipment to the most newest active work location on the project. A vent shaft for the tunnel will be drilled near Maple and Silver Street, which will allow air to escape from the tunnel when it fills with stormwater during rain events.
Previous Site Photo Links
Select the links below to view and download past project photos
September 2025
October 2025
November 2025
December 2025
January 2026
February 2026
March 2026
April 2026
May 2026
June 2026
CBDT Beyond the Site
This section includes major project milestones, TBM details, and miscellaneous photos of important project components that support the mining operation or major construction.
Project Milestone Photos
June 2026 - Delivery of two sections (sheilds) of the Tunnel Boring Machine arrive in Manchester from Germany (via Portsmouth, NH)
June 2026 - The Tunnel Boring Machine Arrives at the Launch Zone
June 2026 - The Tunnel Boring Machine Cutterhead Arrives at the Launch Zone
June 2026 - Placement of the Tunnel Boring Machine Front Shield into the launch zone excavation with members of the project team watching.
June 2026 - Drop Shaft 2 Rock Excavation is completed
June 2026 - The end of Drop Shaft 2 adit is completed. This rock face is the location that the DS-2 adit will connect to the tunnel, once the TBM mines past this location.
Tunnel Boring Machine (TBM) Photos
Tunnel Boring Machine cutterhead under fabrication in Germany
Tunnel Boring Machine interior with segment mold on conveyor, under fabrication in Germany
Tunnel Boring Machine interior behind the cutterhead, 16 cylinders that help push and drive, under fabrication in Germany
Tunnel Boring Machine interior precast concrete segment conveyor
Project Support Photos
Tunnel Segment Forms - Used to pour precast concrete tunnel liner segments at the remote production plant in Connecticut
Completed precast concrete tunnel segments - These pieces will be delivered from Connecticut to the launch zone site and stored until they are ready to be placed in the tunnel. These segments will be part of the finished tunnel walls.
Tunnel Boring Machine push frame design - Used at the start of the tunnel to push the tunneling machine into the ground
Tunnel Boring Machine push frame - The vertical section of the push frame assembly
Slurry plant installation at the Launch Zone. This plant is used to produce a thick liquid that will be pumped to the front of the Tunnel Boring Machine cutterhead. This slurry will support the excavated face of the tunnel and will also be used to carry the mined material from the tunnel back to the production plant.