Currently, the more common way to construct tunnels is a tunnel boring machine (tbm). A tbm is a cylindrical machine with a cross section designed to cut through many types of soil and rock.
How Tunnels Are Built?
Tunnels are one of the most remarkable engineering accomplishments of modern times. Built with a variety of techniques, tunnels provide an efficient and cost-effective way to move goods, people and even water from one point to another. Whether large or small, tunnels are an impressive feat of engineering and require a great deal of planning, preparation and skill to build.
The process of constructing a tunnel begins with a plan. Engineers must take into consideration the terrain, the purpose of the tunnel and environmental factors. Once the plan is created, a survey is conducted to determine the exact route and depth of the tunnel. During the survey, engineers measure the terrain and identify any potential obstacles that may impede the construction process.
The next step is to begin the excavation process. Depending on the type of tunnel, excavation can be done by either hand or with the help of machinery. For larger tunnels, excavators, bulldozers and other large machinery are used to dig out the tunnel. For smaller tunnels, hand tools like shovels and picks are used.
Once the excavation is complete, the walls and ceiling of the tunnel need to be reinforced. This is done by installing a lining, which serves to protect the tunnel from water and other elements that could damage it over time.