TBM 2 (also known as TBM B - not exactly inspiring names I know) recently completed Tunnel 6 and broke through to Muguagou Culvert.  These photos were taken on the traverse across the culvert.  One day I'll get around to writing a bit more bout the project!  Oh... I nearly forgot: TBM means Tunnel Boring Machine.  This one has a 4.9m diameter and is made made by Robbins of the US.  The machine achieved an average daily advance of about 30m.  

The business end - the cutter head.  Roller cutters are mounted in the head to grind the rock, which is scooped up in buckets and transported back by conveyor belt.  The spoil is deposited into muck trains that remove the debris from the tunnel by rail. 

The tunnel is lined as excavation advances.  Interlocking hexagonal pre-cast concrete segments are used, giving the the tunnel the finished lining shown above.  The rails are on the back-up section of the TBM. 

The segments are lined up ready for placement as part of the continuous advance/lining system

The segments are installed using a hydraulic erector.  Here an invert segment is being placed on the traverse of Muguagou culvert.  In tunnel sections, each ring is made up of four segments.  The TBM advances by thrusting off the previously built ring and by gripping the sides of the tunnel

Two of our intrepid team ensure everything is running smoothly

The TBM enters the previously constructed culvert section

The Elmers in China Photo Gallery produced by Richard Elmer.   If you have any comments or want to use any photos, drop me a line!  Revised: 16 Jul 2007 09:42:23 +0100.