On August 20: "70 days, 6,563 piles—we will definitely complete them on time and with quality and quantity guaranteed!" This was the pledge made by Pi Yuanming, project manager of the Flex Phase II project, taking the lead at the Wangcheng Economic Development Zone project construction promotion meeting. The Flex (Phase II) project has a total investment of 2.5 billion yuan, covers 260 mu of land, and has a building area of approximately 258,000 square meters. The pile foundation comprises a total of 6,563 piles, with a cost of 160 million yuan.
From the rapid mobilization on June 28 to the completion of pile foundation construction on August 18, the project took only 51 days, completing all construction tasks 19 days ahead of schedule and delivering a perfect result to the company and the government. However, "6,563 piles (including 74 tower crane piles) must be driven within 70 days; equipment mobilization, installation, and commissioning cannot afford delays in any step." To ensure progress, equipment operated 24 hours a day without stopping, and personnel worked in "two shifts." Only this unconventional working model ensured the orderly advancement of construction tasks.
For the drilling of each pile hole, the inspection reporting system must be strictly implemented, with representatives from all parties conducting on-site joint acceptance: Step one, lower the measuring rope, and after multiple parties confirm that the sounding weight has reached the bottom of the hole, read the pile hole depth and take photographic records; step two, review and calculate the drilling depth according to the design drawings and geological survey data to ensure the rock-socketed depth meets requirements; step three, the owner's representative verifies the slag sample and measures the sediment thickness. After joint confirmation by the "five parties," everyone signs the preliminary acceptance form in sequence.
Because the Flex Phase II project is located in a high-fill area, the geological conditions at the construction site are complex, pile hole collapse was severe, and combined with Changsha's continuous high temperatures and extreme heat, work crews changed frequently, causing construction to fall into a bottleneck for a time. As 15 days passed and the daily output of 20 rotary drilling rigs was only 30 piles, project manager Pi Yuanming was extremely anxious: "At this rate, construction progress will definitely be slowed down; the pile foundation type selection must be optimized."
On July 10, with the participation of experts from all sides, the owner, and the supervisor, a special meeting on pile foundation type selection and construction plans was held. This meeting became a major turning point in the entire pile foundation construction phase. At the meeting, project manager Pi Yuanming and chief engineer Li Cheng gave a detailed report based on actual site conditions and the results of pipe pile and long spiral test piles conducted for the project, explaining the necessity of introducing long spiral and pipe piles from the aspects of efficiency, cost, safety, and quality. The meeting determined a construction plan mainly based on rotary drilled piles, with long spiral and pipe piles used in local areas with complex geology and greater difficulty. The plan won the support and recognition of the owner, supervisor, and all participating parties. After the meeting, the project quickly organized equipment and materials to enter the site. On July 15, the first hydraulic hammer was put into operation, and on July 20, the first long spiral rig was put into operation. In just a few days, output rose sharply. As equipment was gradually commissioned, the project's daily output ultimately increased from 30 piles to 200 piles. At peak, daily output reached 260 piles, with more than 100 large pieces of equipment deployed (rotary drilling rigs, long spiral rigs, hydraulic hammers, truck cranes, etc.). On August 18, with the completion and acceptance of the last pile hole, all 6,563 piles at the project site were completed, taking 51 days and completing all tasks delivered by the owner ahead of schedule.
Kong Yucheng, Secretary of the Wangcheng District Party Committee, said confidently: "The Flex Intelligent Industrial Park has brought together the best enterprise, the best design unit, and the best construction unit, so we must go all out to build the best intelligent industrial park in Wangcheng District." Tian Weiguo, Party Committee Secretary and Chairman of China Construction Fifth Engineering Division, said when visiting senior representatives of Wangcheng District: "As the 'Number One' project of China Construction Fifth Engineering Division, the Flex project will not fail its mission; the Division will make every effort to ensure efficient performance of the project."