The vehicle was driving near the exit of Tianshan Shengli Tunnel on the Urumqi-Yuli Expressway in Xinjiang. Photo by Zhao Huafeng
On the seventh day of the first lunar month, the wanderer embarked on his return journey. The Tianshan Shengli Tunnel, the "throat" of the G0711 Urumqi-Yuli Expressway, is brightly lit, and vehicles loaded with care are shuttled back and forth.
Facing the first Spring Festival travel rush, the world's longest highway tunnel has become a transportation artery connecting northern and southern Xinjiang. The average daily traffic volume during the Spring Festival holiday exceeded 34,000 vehicles, and the average daily traffic volume during peak hours exceeded 45,000 vehicles.
In the snowy Tianshan Mountains, with temperatures as low as minus 30 degrees Celsius, how could the Tianshan Victory Tunnel successfully pass its first "big test" and achieve smooth traffic in an extremely cold environment?
"We have tailor-made a set of 'super anti-freeze' systems for the tunnel to protect the Spring Festival transportation during the cold wave." Miao Baodong, chief engineer of CCCC Xinjiang Transportation Investment and Development Co., Ltd. said.
First put a "warm coat" on the pipes to ensure that the drainage system is functioning properly.
“When traveling in ultra-long tunnels, we are most afraid of freezing pipes.” Miao Baodong explained that especially in winter, the moisture accumulated in the mountain in summer will leak out from the top of the tunnel and the lining and condense into ice, posing hidden dangers to driving safety.
The construction team excavated an ultra-long and deeply buried central ditch at the entrance and exit of the tunnel. Through the deep burial design, the ditch was kept away from the frozen soil layer and the risk of freezing was reduced from the source. At the same time, all transverse water pipes connected to the ditch are wrapped with flexible foam rubber and plastic insulation materials, which is like putting a "warm coat" on the pipes to prevent the water in the pipes from freezing and blocking, and ensure the normal operation of the drainage system all day long.
Then build a thick "cold-proof wall" at the entrance to prevent the tunnel structure from freezing and cracking.
The tunnel entrance is the "throat zone" for internal and external temperature exchange, and is also a key node for anti-freeze. The Tianshan area has a high altitude and is in a low temperature state for about half of the year. Traditional local anti-freeze measures are difficult to withstand the continuous extreme cold.
"During the construction phase, we innovatively set up an insulating concrete structure of more than 500 meters long, which is equivalent to a thick 'cold-proof wall' and forms a continuous anti-freeze 'buffer zone'." Miao Baodong said, this not only ensures the stability of the tunnel structure, but also creates a safe road environment for passing vehicles. It has become a useful exploration of the anti-freeze structure of long tunnels in alpine regions.
Not afraid of wind, snow or freezing, you need to have a good "foundation" and good "maintenance".
In the tunnel, there is a constant flow of vehicles; on the large surveillance screen, the "holographic" picture can be seen at a glance.
This is the holographic intelligent monitoring center of Tianshan Shengli Tunnel – the holographic far and near-view cameras deployed in the tunnel are like pairs of sharp eyes. After the multi-channel video collected by the "brain" is fused and reconstructed, a real-time, dynamic, digital twin tunnel that can be observed from any perspective is generated on the large screen.
"The Tianshan Shengli Tunnel is long, and manual inspections take several hours at a time. The traditional 'manual inspection + fixed camera' model is completely ineffective here." Qi Zhijun, chief engineer of the project of CCCC Electrical and Mechanical Bureau, told reporters that to control this "long underground dragon", it must be equipped with a "smart brain" that can thoroughly perceive, think overall, and respond quickly.
Relying on this monitoring network, the tunnel operation team has realized joint logistics linkage with meteorological, emergency, fire and other departments. During the Spring Festival travel period, personnel are on standby 24 hours a day. Once an accident occurs, they can quickly handle and provide service guidance, effectively ensuring the orderly and smooth flow of large traffic during the Spring Festival travel season.
"The hard foundation combined with the soft power can ensure that key facilities will not 'strike' even in extreme low temperature weather, and build a strong defense line for the safe operation of the tunnel." Miao Baodong said that now that the tunnel is open, it only takes 20 minutes to cross the Tianshan Mountains. With this anti-freeze "combination boxing", they will protect the tunnel every 24 hours.
