What are the types and shapes of tunnels?
What are the types and shapes of tunnels? Tunnels are usually built in rectangular, circular, and horseshoe shapes.
What is the most common shape of tunnels?
Circular tunnels are the most popular shapes in urban underground transportation systems when mechanised tunnelling is used for the tunnel excavation. However, circular tunnels have a small space utilisation ratio.
What is the best shape for a tunnel?
In tunnel engineering, various tunnel shapes are adopted [3], although the circular tunnel is usually preferred due to convenient construction and function layout requirements.