The document discusses various tunnel construction methods. It begins with an introduction to tunnels and their purposes. It then covers traditional/classical methods that were used until the late 19th century such as the English, German, and Austrian systems which involved hand excavation and timber supports. More modern methods discussed include cut-and-cover, drill-and-blast, tunnel boring machines (TBMs), immersed tunnels, and tunnel jacking. Factors in choosing a method include geological conditions, tunnel size/length, surface impacts, and construction speed/costs.