Explanation of different shapes of tunnels
Types of tunnels with detailed explanation:-
The Circular section offers greater resistance to external pressure and highly suitable for unstable ground such as sand or soft clay. They are not used as traffic tunnels because they require more filling to make flat base, hence used for carrying water and sewage under pressure.
Elliptical section have narrower cross section at bottom and top.They also resist external pressures. Due to compactness from bottom and top they better serve as water and sewage conveyance.
Egg shaped section properties are somewhat similar to elliptical section but here the section is narrower at bottom. Due to narrow section at top and bottom both of them are difficult to construct and are used for soft subsoil.
Horse shoe section forms a semi-circular section at the top and curved trapezium shape at the bottom. Hence most preferably used as traffic tunnels on both roads and railways.
Segmental section is mainly used by railways in some countries, because of its vertical walls and flat floors at the bottom side and also forms a semicircular section at the top.
The content shown above is for study purpose only.