The construction site of Dalian Jinzhouwan International Airport Project. Photo by Zhou Yanan (Provided by Dalian International Airport Group)
In the coldest days of winter, on the Bohai Sea side of the artificial island of Dalian Jinzhouwan International Airport Project, the surging waves are frozen by the cold snap, and all that meets the eye is a vast expanse of ice. Meanwhile, the construction progress of the deep foundation treatment project inside the artificial island has not slowed down due to the severe cold.
At the end of 2025, the main part of the 20.1-square-kilometer land reclamation project for Dalian's new airport was successfully completed. Immediately afterwards, it faced the dual challenges of the low-temperature construction environment in winter and the high standards of deep foundation treatment. Instead of adopting a one-size-fits-all winter break mode, the project construction tailored a refined and differentiated winter construction plan according to different geological conditions and process characteristics, laying a solid foundation for the project quality in the severe cold to ensure that every inch of land of this world-class offshore airport is as solid as a rock and every part of the foundation becomes a firm guarantee for the safe takeoff and landing of future flights.
The process cannot stop, and the progress cannot wait
With the temperature dropping below -10℃ and the perceived temperature as low as -21℃, at the construction site of the mud storage area, construction workers are inserting drainage boards one by one into the soft soil layer 5 meters deep in the cold wind. Walking on this soft soil covered with a vacuum membrane, every step sinks softly underfoot.
"The soft soil in the mud storage area now has a high water content. Through the vacuum combined with surcharge preloading process, we run the negative pressure drainage continuously for 24 hours and cooperate with the surcharge of a 10-meter gravel layer. It is expected to achieve a settlement effect of 3 to 4 meters in one year," Sun Min, the deputy commander of the Engineering Construction Command of Dalian International Airport Group Co., Ltd. and the deputy general manager of Dalian Airport Construction and Development Co., Ltd., told reporters. Once this system is started, the negative pressure drainage environment needs to be maintained continuously. If the work stops midway, not only will the consolidation process be interrupted, but the drainage system will also freeze and become blocked, and the previous investment may be in vain.
The craftsmanship cannot be halted, and the progress cannot wait. Sun Min introduced that the silt area underfoot will be used as the apron and vertical taxiways, which are the core parts of the new airport. It is the "pilot section" and "controlling project" of the entire project. Only after the foundation treatment reaches the designed strength can the subsequent main ground works be fully carried out. "Continuing work in winter can gain nearly 100 days of effective construction time, minimizing the impact of seasonal factors, ensuring the project progresses as planned, and laying a solid foundation for the future airport to be put into operation on schedule," said Sun Min.
Effective Cold-proof Measures and Technical Support
At the construction site, nearly 200 white thermal insulation sheds distributed at intervals are very eye-catching. Sun Min introduced that these are the "greenhouses" specially designed to ensure the normal operation of the negative-pressure drainage equipment. Inside the insulation sheds, the vacuum pumps wrapped in thermal insulation cotton keep roaring. The inspection personnel walk between the sheds, checking the readings of thermometers and pressure gauges one by one to confirm the operating status of the equipment.
"Facing the construction challenge of continuous low-temperature, we have taken thermal insulation and freeze-prevention measures for the whole system. Meanwhile, through dual monitoring of manual inspections and digital means, we ensure 24-hour continuous monitoring, maintaining the bottom line of efficiency and safety in the severe cold," said Sun Min.
At present, multiple processes such as vacuum combined surcharge preloading, dynamic compaction, and gravel pile of the deep foundation treatment project are being carried out simultaneously. In addition to putting "winter clothes" on the core equipment, regarding the work-time arrangement for construction workers, the vacuum combined surcharge preloading duty positions operate in three shifts, with non-stop work throughout the day; the rest of the construction gives priority to the window period when the temperature is higher during the day. The construction workers work in two-hour rotations to avoid long-term exposure to the cold outdoors. Temporary warming and rest points provide hot drinks at any time, and all construction workers are equipped with cold-proof labor protection supplies, making the builders feel warm in the cold days.
Every Blow Counts
A 90-ton rammer falls from a height of 20 meters. A single-point foundation needs to withstand 18 such powerful rammers to meet the construction standards. In the complex multi-line construction, how to ensure that every foundation and every process strictly meet the standards? The answer lies in the "second site" of the project construction-the intelligent construction command center.
Inside the command center, the large screen of the digital construction monitoring system is always on. Different construction plots are clearly distinguished by colors, and the schematic icons of dispatched vehicles and construction machinery are updated synchronously as their on-site positions move, making the construction dynamics clear at a glance. "Taking the dynamic compaction process as an example, we have installed sensors on each rammer. Key information such as the number of rammers and the ramming time can be traced throughout the process in the system," Sun Min introduced. Once the number of rammers fails to reach the preset standard, the system will automatically give an alarm, and the monitoring personnel will immediately notify the on-site inspection and treatment to ensure that no construction quality hidden danger is missed.
In addition, the project has also established a digital monitoring system covering the entire life cycle and the whole area of the project, ensuring that from land reclamation to deep foundation treatment and then to the subsequent construction of the flight area, all monitoring data can be continuously checked, effectively preventing and controlling foundation settlement, and keeping the settlement volume in a balanced and controllable state.
Technology "Breaks the Game" to Lay a Foundation for Long-term Operation
As the first offshore airport in China, the Dalian New Airport project faces difficulties such as deep soft foundation, complex geological conditions, and high requirements for foundation settlement and differential settlement, which puts forward higher requirements for construction standards. The importance of the deep foundation treatment project is self-evident. Sun Min said that through this project, differential settlement can be accurately controlled to ensure flight safety. At the same time, it can cooperate with the revetment barrier to enhance anti-scouring and anti-erosion abilities, taking into account ecological protection and extreme weather response, and laying a foundation for long-term operation.
For the geological characteristics of different regions, the project innovatively adopts foundation treatment technologies such as ultra-high-energy dynamic compaction and ultra-high-pressure vacuum combined surcharge preloading. Relying on the digital management and control platform, a Building Information Model (BIM) is established to achieve full-process closed-loop management and control. "These breakthroughs not only construct a settlement control technology system for offshore airports, filling the gap in similar engineering technologies, but also provide a replicable technology and management model for the industry, strongly promoting the digital and intelligent upgrading of marine engineering," said Sun Min.
According to the plan, in the near future, the Dalian New Airport project will build two long-distance parallel runways and a 500,000-square-meter T1 terminal. After completion, it can meet the operation needs of an annual passenger throughput of 43 million, a cargo and mail throughput of 550,000 tons, and 330,000 flight take-offs and landings. "In 2026, in terms of deep foundation treatment, we will fully promote the foundation treatment works of two parallel runways and two vertical taxiways, strive to meet the construction standards by the end of the year, and create conditions for the subsequent ground works," said Sun Min.
