Concrete pipe, also known as reinforced concrete pipe, serves as the foundation for urban construction's下水道, wastewater discharge, flood control drainage, and water pipes for special factories and mines, as well as irrigation wells for farmland. It is generally categorized into: flat reinforced concrete cement pipes, socket reinforced concrete cement pipes, flexible joint reinforced concrete cement pipes, and so on.
Plain-end reinforced concrete cement pipe
The plain end reinforced concrete cement pipe is an early interface method with low production difficulty, high efficiency, and low production costs. The wire mesh concrete strip is used for interface sealing, but it offers poor rigid connection sealing and poor seismic performance. Foundation displacement can open the interface, leading to the leakage of wastewater and damage to road collapses. Wastewater pollution of soil and groundwater on both sides of the pipeline poses significant social hazards; the pipeline foundation should be a concrete foundation. Construction efficiency is low, costs are high, and construction cannot be carried out during winter or rushed. Therefore, the application of plain end reinforced concrete cement pipes in municipal drainage and sewage projects is decreasing.
2. Insert and socket reinforced concrete cement pipes
The precast concrete pipe with socket and spigot joints began to be promoted in the late 1980s. Sealed with rubber rings (sliding rubber rings offer better sealing than rolling ones), these joints are flexible, with an insertion depth of 80-100mm and a relative angle of 1.5° at the joint. They have good seismic performance and can resist uneven foundation settlement. However, it is difficult to control the depth of the socket base pit, and backfilling is not always dense, leading to high stress concentration at the socket and pipe body transition, which can cause annular cracks and pose safety risks. Therefore, large-diameter pipelines should not be made of socket-type reinforced concrete pipes. For pipe diameters of 1200mm or less (DN1200), socket and spigot joints should be used instead.
3. Flexible Enterprise口中Reinforced Concrete Cement Pipe
Flexible expansion joint reinforced concrete pipe was introduced at the end of the 1990s. It primarily uses sliding rubber rings for sealing joints with diameters greater than DN1200, providing flexible connections. The insertion depth is approximately 135mm, deeper than the spigot socket, with a relative angle of 1.5°. The joints offer excellent seismic resistance and can effectively withstand uneven settlement of the foundation. The pipeline foundation can be either sandy or concrete, with faster installation speed and better operating points than socketed joints. The construction cost of flexible expansion joint reinforced concrete pipe is lower than that of socketed joints, as the trench width for socketed joints is wider, increasing the filling volume, especially for large-diameter pipes. Therefore, choosing flexible expansion joint reinforced concrete pipe can save engineering costs. The installation pit depth for socketed joints is difficult to control, and backfilling is not dense, leading to excessive stress concentration in the pipeline spigot, which can cause hoop cracks in the pipe body in severe cases, affecting the service life of the pipeline. The flexible expansion joint reinforced concrete pipe has good contact with the foundation, with uniform load-bearing capacity and enhanced safety. The spigot of socketed reinforced concrete pipes has an inclined outer wall, making it challenging to control during the construction of inspection wells, but it is easier to improve.
