What types of tunnels are there?

Tunnels can be classified into several types based on their purpose and construction methods. The main categories include transportation tunnels (for vehicles, trains, or pedestrians), utility tunnels (for water, sewage, electricity, or telecommunications), and mining tunnels (for resource extraction). Construction methods vary, with options like cut-and-cover, bored, and immersed tunnels, each suited for different geological conditions and project requirements. Additionally, tunnels can be categorized by their location, such as underground, underwater, or mountain tunnels.