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TBM Angeli reaches another milestone

02/01/2018

The TBM Angeli being used for the Regional Connector resurfaced on the 08 Dec 2017 at the future Grand Avenue Arts/Bunker Hill Station. The TBM began digging the second tunnel on the project in late September and travelled approximately 1,340 m (4,400 feet) from Little Tokyo to reach the deepest station on the alignment. 

A lot was learned from building the first tunnel which has been used to dramatically increase the rate of production on this tunnel. Typically, TBMs will travel 18.29 m (60 feet) to 30.48 m (100 feet) per day when working in similar soil conditions. This TBM, however, travelled a maximum of 57.91 m (190 feet) in a single day and averaged more than 122 m (400 feet) per week. Crews have erected 739 precast concrete rings to build the tunnel so far. 

The TBM is now being walked across the station and re-launched at the west end. To complete the second tunnel, the TBM will need to dig through another 417.58 m (1,370 feet) of soil to reach the extraction point at the intersection of 4th and Flower streets in January. 

The project is forecast to be completed by December 2021. Click here for the video and here for tunnelbuilder archive. Visit https://www.metro.net.



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