What is the difference between a tunnel and a culvert?

First of all, the definition is different:

1. A tunnel is defined as an underground cavern with a specified shape and size and a cross-sectional area of more than 2 square meters, which is built for a certain purpose by any method.

2. Culvert refers to the drainage tunnel (water passage) built under subgrade and pavement in order to make the highway pass through the canal smoothly and not hinder traffic. Through this structure, water can flow under the highway.

Second, the use is different:

1. Tunnel is an engineering building buried in the stratum, and it is a form of human using underground space. Tunnels can be divided into traffic tunnels, hydraulic tunnels, municipal tunnels and mine tunnels.

2. Culvert is a small ground drainage structure that crosses the subgrade where the channel passes through the highway. In order not to hinder the traffic, when the embankment passes through the depression or the ditch, the water above the subgrade is discharged to the bottom.

Third, the size and depth are different:

1, the cross-sectional area of tunnel construction is more than 2 square meters.

2. Culverts generally pass through the lower part of the embankment, and most of them are filled at the top of the tunnel, using single holes or double holes with an aperture of 0.75 ~ 6 m. The calculated span L of single span is less than 5m, and the total length of multi-hole span (that is, L 1) is not strictly regulated.

Fourth, the structure is different:

1. The structure of the tunnel consists of two parts: the main building and auxiliary equipment. The main building consists of a tunnel body and a hole, and the auxiliary equipment includes a car-avoiding tunnel, fire-fighting facilities, emergency communication and waterproof and drainage facilities. This long tunnel also has special ventilation and lighting equipment.

2. Culvert is a drainage tunnel under subgrade, which usually consists of two parts: tunnel body and portal building. The tunnel body is composed of several pipe joints and is the main body of the culvert. Buried in subgrade, there is a certain longitudinal slope to facilitate drainage; The end wall and wing wall are located at the entrance, exit and both sides, which play the role of retaining soil and guiding water, and can also protect the embankment slope from water erosion.

Five, the classification is different:

1. Tunnels are divided into: railway tunnel, pedestrian tunnel, canal tunnel, water conveyance tunnel, drainage tunnel (sewer is one of them), mountain tunnel (vehicles crossing mountains to reduce driving distance), urban underground tunnel, underwater tunnel, submarine tunnel (tunnels built by vehicles under the sea to connect the two sides of the Taiwan Province Strait), river-crossing tunnel, cable tunnel and subway tunnel.

2. According to different standards, culverts can be divided into many types. According to building materials, it can be divided into brick culvert, stone culvert, concrete culvert and reinforced concrete culvert; According to the structural form, culverts can be divided into circular tube culvert, arch culvert, slab culvert and box culvert.

According to the different classification of filling conditions, culverts can be divided into open culverts and concealed culverts. Open culvert means that there is no fill at the top of the cave, which is suitable for low embankment and shallow ditch. There is fill at the top of culvert, and the minimum thickness of fill should be more than 50cm, which is suitable for high embankment and deep ditch. According to the classification of hydraulic performance, culverts can be divided into pressureless culverts, semi-pressure culverts and pressure culverts.

An unpressurized culvert refers to a culvert where the water level at the entrance is lower than the upper edge of the entrance and the water level does not touch the top of the entrance within the whole length of the entrance. Semi-confined culvert refers to a culvert with the water level at the entrance higher than the upper edge of the entrance and the head pressure at the top of the entrance. Inlet and outlet water of pressure culvert, full-face drainage of culvert.

Extended data:

Cross-harbour tunnel is a technical project to build a traffic pipeline under the seabed of straits, bays and estuaries to communicate land traffic. Submarine tunnels are generally divided into two types: submarine surface and submarine stratum, and their construction methods are different. The cross-harbour tunnel does not hinder the navigation of ships on the water and is not affected by meteorological conditions such as strong winds and fog. World-famous subsea tunnels include Tongben Han Qing Tunnel and Anglo-French Channel Tunnel.

The English Channel Tunnel, also known as the British-French Cross-Harbour Tunnel or the European Tunnel, is a railway tunnel connecting the British Isles with Europe and France. Opened on May 6th, 1994. It consists of three parallel tunnels with a length of 5 1km, with a total length of 153km, of which the subsea tunnel is 3×38km, which is the longest subsea tunnel in the world at present.

The diameter of the two railway tunnels after lining is 7.6m, and the diameter of the excavated tunnel is 8.36 ~ 8.78 m; The diameter of the central logistics service tunnel after lining is 4.8m, and the diameter of the excavated tunnel is 5.38~5.77m It took more than 8 years from1February 1986 when Britain and France signed the Canterbury Treaty to1May 7, 1994 when the tunnel was officially opened. This is the largest private capital project in the world.

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