In Seattle, WA contractor STP is making final preparations for TBM Bertha’s move into the 36.57 m-deep pit from which the machine will be hoisted to surface for repairs. STP has injected grout into the ground and installed new drains alongside the TBM to control groundwater as Bertha slowly moves forward through the wall of the pit. They will use heavy equipment to chip away the portion of the pit’s southern wall where Bertha will emerge. Approximately 6 m of unreinforced concrete stands between Bertha and daylight, so the dig will depend on her ability to mine through and digest concrete while operating with a damaged seal system. STP expects some overheating, similar to that experienced during their most recent attempts at mining. They will likely mine until the machine becomes too hot, then take a break. To speed up the move, crews may choose to continue chipping their way toward Bertha from within the pit during times when the machine is cooling off. Moving Bertha into the pit is just the beginning of the repair process: before the machine can be lifted to the surface by this massive crane, it has to be partially disassembled. Click us/69 and here for tunnelbuilder archive. Visit http://www.wsdot.wa.gov. 08/15.