Over the years, engineers have come up with many different methods of tunnel construction to make the process more efficient and safer. One such method is the tunneling shield, which was first developed by British-French engineer Marc Isambard Brunel in 1818. Brunel observed how barnacles could burrow through wood, so he applied this concept to create a giant rectangular cast-iron cavity that could be used to tunnel underground. The tunneling shield worked by resting against the earth, opening steadily to allow workers to dig through the soft soil outside, and pushing the shield face forward with a screw jack. This method led to the first underwater tunnel built under the River Thames in London in 1842. Today’s tunneling shields are cylindrical in shape and made from steel, with hydraulic jacks to push them forward.
When digging through rock layers, modern technology takes over with tunnel boring machines (TBM). These machines have revolutionized construction by using a rotating cutting head that digs through rock layers ahead. They apply pressure to the rock, causing it to crack and then convey it away via a conveyor belt. The English Channel Tunnel was built using 11 TBM machines that dug 56.3 km long tunnels at a depth of 45 m below sea level.
Another innovative method of tunnel construction is submerged tube tunnels, developed by American engineer WJ Wilgus. This technique involves building a tunnel from prefabricated pipe sections elsewhere and then submerging and positioning them in a dredged trench in a riverbed or seabed. Once buried, they restore the seabed.
These various methods demonstrate how far we’ve come in our evolution of tunnel construction over time. Advancements in technology and engineering have resulted in more efficient and safer processes for engineers to choose from based on specific project requirements.
In conclusion, whether you use tunneling shields or TBMs or submerged tube tunnels, your goal remains the same: creating secure and reliable underground passages for transportation or other purposes. Engineers are constantly working hard to develop new methods that will lead us closer towards achieving this goal while also making sure everyone’s safety is taken into consideration throughout each step of the process.
