Culvert is a small ground drainage structure that crosses subgrade when subgrade passes through depression or ditch (canal), or discharges the water collected above subgrade to the bottom. There are many kinds of culverts, and their cross-sectional shapes, entrance and exit types and water flow patterns in culverts are also different.
culvert
Culvert consists of tunnel body, portal building, foundation and ancillary works. Cave body is the main part of culvert, and its cross section is round, arch and box. The entrance building is located at both ends of the culvert and has two structural forms: I-shaped wall and I-shaped wall. There are two forms of foundation: integral and non-integral. Auxiliary works of culvert include: cone slope protection, river bed paving, subgrade slope paving, artificial waterway, etc.
The gatehouse is generally composed of three parts: water inlet, water outlet and trench bed reinforcement. Its function is to connect the culvert with the river smoothly, so that the water can flow in and out smoothly, and at the same time, it also plays a role in protecting the subgrade slope from water erosion. There are many types of openings, such as figure-eight, end wall, falling well, twisted slope and flat head.
Culvert action
Culverts are used where canals cross roads. In order not to hinder the traffic, cross culverts are built under the sidewalks to let the water flow under the roads and turn to the ground. They are tubular, box-shaped and arched. According to the principle of connector, it is usually made of brick, stone, concrete, reinforced concrete and other materials.
Conditions of use
Reinforced concrete pipe culvert is suitable for small-span concealed culvert with sufficient fill height in stone-deficient areas, generally using single hole, and it should not exceed 3 holes when porous. Reinforced concrete slab culvert is suitable for open culvert or concealed culvert in stone-free area with large water area. Arch culvert is suitable for crossing deep ditch or high embankment.
Stone cover plate is suitable for small culverts with rich stone and small water flow. Inverted siphon culvert is suitable for irrigation channels when the excavation height of cutting can't meet the requirement of aqueduct clearance, but not for steel corrugated pipe culvert in flood drainage ditch. It is suitable for subgrade with low bearing capacity or large settlement deformation.