On the morning of November 13, the Phase I project of the CCCC Chongqing Cold Chain Smart Industrial Park successfully completed all pile foundation construction—1,905 piles with a total length of about 30,000 meters—ahead of the schedule milestone, laying the foundation for the next stage: advancing the above-ground main structure of the industrial park.

This will be the first green smart cold chain project with an ultra-low-temperature warehouse in Southwest China. It can serve the Southwest region centered on Chongqing, focusing on four major functions: a fresh food warehousing and distribution center, a processing and central kitchen center, a government emergency supplies reserve center, and a comprehensive exhibition and trading center. It will meet the consumption needs of urban residents and become a "super-large refrigerator" at the doorstep of the public in the Chengdu-Chongqing region!

Rendering of the CCCC Chongqing Cold Chain Smart Industrial Park project

The CCCC Chongqing Cold Chain Smart Industrial Park project is located in Shapingba District, in the core hinterland of Chongqing's central urban area, with superior locational conditions. The project is close to the seat of the Shapingba District government and the departure station and container marshalling yard of the China-Europe Railway Express and the rail-sea intermodal trains of the New International Land-Sea Trade Corridor. It is adjacent to the urban expressway network, within 25 kilometers of the core commercial district, and can reach the core main urban area within 30 minutes.

The project is invested in, constructed, and operated by CCCC Fourth Harbor Engineering Co., Ltd. (CCCC Fourth Harbor), the main engineering bureau under China Communications Construction Company Limited (CCCC), a central state-owned enterprise ranked 63rd in the Fortune Global 500. With a total investment of 1.352 billion yuan, it covers 225 mu and has a total floor area of 181,000 square meters. The planned construction content includes a cold chain warehousing and distribution center, a multi-temperature-zone logistics center, a constant-temperature and ambient-temperature logistics center, a comprehensive exhibition center, and supporting ancillary facilities. The park's food storage cold rooms cover temperature zones from -55°C to 20°C. Phase I has a total floor area of 91,300 square meters, officially commenced on September 5, 2023, and is scheduled for completion on December 30, 2024.

It is understood that the Phase I project involves 1,905 piles with diameters of 800–1,200 mm and a maximum single-pile length of 32 meters, totaling about 30,000 meters of pile foundation construction. The workload is large, and combined with complex on-site geological conditions and limited construction space, the construction is extremely difficult. Ye Ruiyu, head of the Chongqing Cold Chain Project General Contracting Department of the CCCC Fourth Harbor General Contracting Company, introduced that the project team, aiming to create a national backbone logistics base and a Chongqing Safe Construction Site, set up a Party member technical task force and completed the pile foundation construction milestone ahead of schedule.

Technical personnel of the Chongqing Cold Chain Project of the CCCC Fourth Harbor General Contracting Company

How to optimize the hole-forming technology for the project's pile foundation construction was the key difficulty before pile foundation work began. Yu Hang, technical head of the Chongqing Cold Chain Project General Contracting Department of the CCCC Fourth Harbor General Contracting Company, introduced that the on-site soil layer is backfill soil reaching a depth of 25 meters, with loose soil, strong permeability, and construction waste and silt. It is difficult to form holes during pile foundation construction, and collapse is likely during drilling. The backfill soil has a high porosity, so slurry construction is prone to slurry leakage. All of these greatly affect the safety, quality, cost, and schedule of the project.

Facing construction difficulties and technical challenges, the Party member technical task force conducted multiple simulation tests and comparisons, changed the originally designed construction technology of slurry wall protection and rotary drilling, and decided to adopt a pile foundation hole-forming technology combining "rotary excavation hole-forming" with "temporary steel casings," the "recharge method," and "steel casing follow-up." This not only ensured pile foundation quality and guaranteed construction safety and schedule, but also avoided the environmental pollution caused by the large amount of slurry required by the original design, saving nearly 10 million yuan in costs and laying a solid foundation for subsequent construction.

"At the start of pile foundation construction, it coincided with Chongqing's rainy season. The backfill soil on site softened when exposed to water and was prone to water accumulation, and the roads became muddy, posing challenges to safe and civilized construction on site," Wang Yinglong, deputy manager and deputy safety director of the Chongqing Cold Chain Project General Contracting Department of the CCCC Fourth Harbor General Contracting Company, told reporters. "To ensure construction safety, the project team deepened the drawing design of outdoor pipe networks such as rainwater, fire protection, and electrical circuits in advance before construction, ensuring that rainwater is collected and discharged in an orderly manner during construction and saving time on the later pipe network construction schedule."

"We also temporarily rented more than 200 thick steel plates, 2 meters wide and 6 meters long, and laid them on the main construction road. We brought in more than 200 truckloads—over 4,000 cubic meters—of crushed stone to pave the ground. At the same time, we rented two long-boom pump trucks to ensure concrete pouring for the pile foundations, minimizing the impact of rainy days on construction production." Recalling the scene at the time, Ye Ruiyu still felt that it was raining in his heart—and that he was also playing a game of chess.

The industrial park has a large number and dense arrangement of pile foundation construction, with closely spaced piles—the nearest adjacent piles are only just over 2 meters apart. Considering that continuous piling could not be carried out in the dense pile group and that the piling rig could not be moved frequently, which would affect efficiency, delay the schedule, and increase costs, the project team divided the work into several flow construction sections for skip-pile operation, achieving seamless connection with the next process and ensuring uninterrupted, obstacle-free continuous operation throughout the project.

Facts have proven that Ye Ruiyu and the project team he leads, with the plan, wisdom, and sense of responsibility of a central state-owned enterprise national team, worked intensively for more than two months on the first important milestone of the CCCC Chongqing Cold Chain Smart Industrial Park project—pile foundation construction—and achieved the target ahead of schedule. Recently, the industrial park project has been vigorously carrying out main structure construction and is starting key construction steps such as open-floor foundation work, tower crane installation, and group tower crane anti-collision measures, making every effort to ensure efficient and orderly progress of the project.

Jiang Zhengshun, general manager of CCCC Fourth Harbor (Chongqing) Supply Chain Company, is full of confidence in the project's future: "The project plans to complete topping-out of all main structures by the end of April 2024, complete acceptance in October, and be completed and officially put into operation by the end of December." According to the introduction, the project's investment promotion work is progressing steadily. After the project is put into operation, it will contribute more than 39 million yuan in tax revenue each year and is expected to attract 50–100 upstream and downstream enterprises in the temperature-controlled food supply chain to settle in the park, effectively driving the local economy and employment. The park's total commodity circulation is expected to reach 14 billion yuan per year.