What does the shape of tunnel depend upon?
What does the shape of tunnel depend upon? Determining tunnel shapes requires the consideration of various factors such as ground and groundwater conditions, usage, economic efficiency, and constructability.
What is the common shape of tunnels?
Tunnels are usually built in rectangular, circular, and horseshoe shapes. Studies in this field include works of authors such as Park et al.
What factors should be considered for tunnel?
The design and construction of a tunnel must account for the mechanical properties of the surrounding rock, which includes not only the aforementioned cracks and discontinuities, but also the weathering and deterioration of the rock, the number and type of layers in the rock, strike and dip of these layers, underground ...
Why is an arch usually the preferred shape for a tunnel?
A parabolic arch has been shown to support the weight of the rock above the tunnel much better. The arrangement of stones transfers the weight laterally around the tunnel to the rock below much more efficiently.
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.
How do tunnels not collapse?
Because they're stronger that way. Tunnels are circular to take advantage of the characteristics of soil and rock. Soil and rock are resistant to crushing forces (compressive forces). By rounding the ceiling, the weight of the soil and rock from the top to are balanced over the entire tunnel, increasing its strength.
How long do tunnels last?
Underground structures last a significantly longer life time than above-ground structures. Approximately about 50 years for above-ground, over 100 years for tunnels.