The design of steel-lined pressure tunnels and shafts

The state-of-the-art of the design criteria and the methods for load sharing calculations for steel lined pressure tunnels and shafts is reviewed here. The design methods mainly based on allowable stresses in the steel liner can be questioned if high strength steel is used. After addressing the problematic nature of such steel, the author outlines the application of fracture mechanics theory in the design of steel liners. A new research project is briefly described, where the acoustic signal of waterhammer will be used to access the structural stiffness of steel lined pressure tunnels and shafts.