Letter

摘要

Dear Sir, Regarding the Farnworth Tunnel article (Tunnels and Tunnelling International, February 2016, p.32), since when did an open shield with digger arms become a "TBM"? Maybe the "Japanese-English" term of "shield-machine" would have worked? There used to be an ITA Working Group (WG) defining terminology in a publication, though I am not sure there is a current version. Perhaps someone from that WG could update us? Regardless of that, I am sure most tunnellers use the term 'TBM" to mean a shield with an inbuilt rotating cutter-head. Maybe others would say that definition is now outgrown but a digger-shield (which is what we often called equipment like that used at Farnworth) clearly does not "bore".