UP THE JUNCTION,ROUND THE BEND

摘要

PUSHING A PREFORMED CONCRETE BOX through an excavation to make a ready-lined tunnel is not unknown, in Britain or abroad, but hitherto, at least in this country, the boxes have been rectangular and the pushes have been in a straight line. But inserting a curved portal into a curved excavation - pushing it, as it were, literally round the bend - is something that has not been attempted on these shores.