Tunneling is a complicated and expensive undertaking, whether you're building a mile-long tunnel or a shorter one. The cost of building a 1-mile tunnel depends on various factors, including the type of tunnel, the materials used to build it, the location and terrain, and the method of construction.
Type of tunnel: There are two main types of tunnels: cut-and-cover tunnels and bored tunnels. Cut-and-cover tunnels are typically less expensive to build than bored tunnels, but they can be disruptive to surface traffic during construction. Bored tunnels are built by excavating a large hole in the ground and then lining it with concrete or some other type of liner. Bored tunnels are more expensive to build than cut-and-cover tunnels, but they cause less disruption to surface traffic during construction.
Materials: The type of material used to build a tunnel also affects its cost. Concrete is the most common material used fortunnel linings, but it is also possible to use steel or other materials. The choice of material will affect both the initial cost of constructing the tunnel and the ongoing costs associated with maintaining it.
Location and terrain: The location and terrain where a tunnel is being built can also have an impact on its cost. Tunnels built in difficult terrain or under waterways may be more expensive to construct than those built in more straightforward locations. In addition, tunnelling in urban areas often incurs additional costs due to having to deal with existing infrastructure such as sewers, water mains, and subways.
Construction method: The method used to construct a tunnel can also affect its cost. Tunnel boring machines (TBMs) are typically used for longer tunnels while shooting or drilling methods may be used for shorter ones. TBMs are more expensive than shooting or drilling methods, but they allow for faster construction times which can save money in the long run.
In conclusion, there is no simple answer to how much it costs to build a 1 mile tunnel because there are so many variables that go into such a project!