ABSTRACT
In the autumn of 1989 TML Tunnelling Director John King stood in the UK’s south marine running tunnel and watched in horror as water poured into the excavation and chunks of chalk up to 1 metre deep collapsed onto the boring machine. It was, said King, the low point of the whole project for him. “I stood in the machine with the tunnel superintendent and the water was just flooding in. We knew from the service tunnel excavation that this could happen-but it was on a much larger scale than we expected. We watched the water come in and tried to work out what on earth we were going to do.”
