For a week now, the world’s largest boring machine has sat idle 60 feet below South Main Street as engineers work ‘round-the-clock to figure out what the heck is thwarting Bertha’s road to glory.
Today, Seattle tunnel contractor revealed that it has begun to install up to eight wells, around 120 feet deep on the construction site near the machine. The wells will lower the water pressure in the ground, to create a safe environment for workers to enter the excavation chamber at the front of the machine to begin to assess the situation. High groundwater pressure combined with loose soils has to this point prevented safe worker access.
“We’re confident STP (Seattle Tunnel Partners) has the right people and the right approach in place to safely determine what’s causing the obstruction,” said Matt Preedy, Alaskan Way Viaduct Replacement Program deputy administrator. “Once they know what the obstruction is, our contractor will be able to select the best path forward.”
Well installation started Thursday and will continue into next week. STP hopes to begin inspecting the machine by late next week.
Bertha was stopped dead in her massive tracks last Friday after encountering a mysterious object.
Click here to see SW’s take on what got her stuck.
“We don’t know what it is,” Chris Dixon with Seattle Tunnel Partners said during a news conference Wednesday. “Right now, we’re developing plans to access that area underground to see exactly what it is that’s limiting the progress of the (tunnel boring machine). And it’s going to a while to implement these plans and see what exactly the situation is.”
WSDOT officials, as KING 5 reports, said it could be something stuck in the tunnel boring machine behind the five-story tall cutting head, or something in front of it. WSDOT wants to send men into the tunnel to see Bertha and get eyes on the object.