#265 Tunnelling Innovation: Inventing the Bentonite Shield

Sixty years ago a civil engineer called John Bartlett of Mott, Hay & Anderson had a revolutionary idea. He noticed that bentonite clay could be used in a slurry to stabilise the face of tunnels during excavation. This could prevent non-cohesive, water bearing soils from collapsing inwards making excavation safer and cheaper.   The first...