According to the traditional production process of pipe pile, there is a set of end plate and steel hoop at each end of the prestressed concrete pipe pile. After the end plate, steel hoop and reinforcement framework are assembled, the tensioning head plate and tensioning tail plate shall be assembled. The whole assembly process is fussy, and the weight of tensioning head plate and tensioning tail plate is large, which will result in high labor intensity, low work efficiency, high production cost and waste of resources.

The technology of the project relies on the application of prestressed concrete pipe pile in photovoltaic project. The pipe piles were constructed by drilling method. Only one prestressed concrete pipe pile is used for each foundation, and only one set of end plate and steel hoop of the prestressed concrete pipe pile have practical effect. According to the characteristics that the main steel bars of the reinforcement framework of prestressed concrete pipe pile are consistent and evenly distributed, the traditional tensioning process is adopted at the tensioning end, and the non tensioning end is fixed with the tensioning device. After steaming and curing process, the tensioning device on the non tensioning end is removed for recycling.

Pipe piles in photovoltaic project by drilling method

Application in photovoltaic project

The main innovations of the project are as follows:

l The non tensioned end is assembled with tensioning device, which is composed of steel bar hanging plate, slurry retaining plate, vertical reinforcement and steel pipe. The slurry retaining plate and hanging reinforcement plate are processed with through holes the same as the pipe pile end plate. The diameter and number of holes are determined according to the diameter and number of main steel bars of the reinforcement framework, and the distribution of holes is also consistent with the distribution of main steel bars.

l After demoulding, the reinforcement framework between the steel bar hanging plate and the slurry retaining plate will be cut off by the electric welding machine. After removing the tensioning device, it can be reused.

The tensioning device without end plate for prestressed concrete pipe pile which can be reused after disassembly

Tensioning device without end plate for prestressed concrete pipe pile is assembled with reinforcement framework instead of steel hoop and end plate.

This technology has been successfully applied to 100MW ordinary photovoltaic power station project in which a total of 3500 PHC pipe piles were adopted without end plate tensioning device, and operate stably. For the pipe pile without cutting, only one set of end plate and steel hoop would be used for each pipe pile through this technology which simplifies the operation steps, reduces the assembly time of the reinforcement skeleton, improves the production efficiency and reduces the labor intensity