On August 1, heading east through the urban area of Rui'an, Wenzhou, across the open fields, not a patch of shade could be found. Then, looking up, one suddenly noticed pile drivers nearby, roaring with a "rumble, rumble."

　　To provide a proper "home" for the Rui'an 500 kV power transmission and transformation project, workers braved the high temperatures and were "planting" 4,994 pipe piles into the ground out in the open fields. These pipe piles are cast entirely from concrete, with steel structures at both ends.

4,994 pipe piles linked into a "giant net"

To ensure power supply during the summer peak, how can a smoother and faster "expressway" network be built for power transmission? The 500 kV Rui'an power transmission and transformation project was launched for exactly this purpose.

But in coastal areas, building power transmission and transformation projects faces multiple challenges, including soft foundations and frequent typhoons. "Planting" pipe piles into the ground to form a pile-net composite foundation that tightly "holds" the earth has become the solution.

Pipe piles "planted" one by one underground form a pile-net composite foundation

Walking on the construction site, a blast of heat rushed at one's face. Round holes were left in the ground, with pipe piles stacked nearby. Workers were seen operating buttons back and forth in a cramped control cabin, and with the help of a crane, the pipe piles were slowly driven into the ground. At the joints, welding workers carried out welding operations. Before long, the welders' clothes were soaked through.

"Look, these giant pipe piles are all 'planted' into the ground one by one, with the deepest more than 50 meters down," said Liu Qingdong, project manager of State Grid Zhejiang Construction Company, pointing at a stack of pipe piles. For the entire project, 4,994 such pipe piles are to be driven, at depths ranging from more than 40 meters to more than 50 meters.

After the pipe piles are driven into the ground, planes are also formed below, and the pipe piles are linked into a net, forming a pile-net composite foundation. This is the *** and deepest pile-net composite foundation technology in domestic substation projects, thereby significantly reducing fill settlement.

Construction site