China News Service, September 17 (Reporter Zuo Yukun) High-speed rail, a beautiful Chinese traffic card.
The high-speed railway lines extending in all directions have greatly accelerated the flow of people.
However, in the impression that the high-speed rail passes through, it always seems to be connected with solid land.
Have you ever thought that in the vast sea, you can also raise the rails to support the huge high-speed railway?
On the morning of August 30, at the construction site of the Xiamen North Station of the newly-built Fuzhou-Xiamen Railway, with the smooth laying of the last set of 500-meter-long steel rails, my country's first cross-sea high-speed railway, the newly-built Fu (Zhou) Xiamen (Men) Railway, has been laid across the entire line. .
This cross-sea railway with the highest speed in the world has successively crossed the three bays of Meizhou Bay, Quanzhou Bay and An Bay.
With the fighting spirit of "passing the gate, it is difficult to pass the pass", it reflects the spirit of the Chinese railway of "opening a road in the mountains and building a bridge in the water".
my country's first cross-sea high-speed railway - Fuzhou-Xiamen high-speed railway.
Photo courtesy
Breaking through the problem, the high-speed rail achieves "crossing the sea without slowing down"
The Fuxia-Xiamen high-speed railway is my country's first high-speed railway in a real marine service environment, with a design speed of 350 kilometers per hour.
Fuzhou and Xiamen will realize a "one-hour life circle", and Xiamen, Quanzhou, Zhangzhou and the southern Fujian "Golden Triangle" will form a "half-hour traffic circle".
A new era of China's high-speed rail across the sea will also come.
In the construction of this trans-era cross-sea railway, there are not only the problems of complex marine hydrological environment and high risk factor, but also three extremely difficult construction sites in Meizhou Bay, Quanzhou Bay and An Bay. Dare to break through?
Difficulties do not overwhelm the Chinese railway people.
On August 4, the last part of the "three major difficulties" of the Fuzhou-Xiamen high-speed railway, the Anhaiwan Bridge, completed the construction of the ballastless track.
The Anhaiwan Bridge, designed by the Fourth Institute of China Railway Construction and constructed by the China Railway Construction Bridge Bureau, is one of the controlled projects of the Fuzhou-Xiamen high-speed railway line.
The completion of this project is not only the "sealing" of the Fuzhou-Xiamen high-speed rail bridge, but also the "big-span" sea-crossing "mountain" of the world's ballastless rail bridges.
For the first time in the course of my country's high-speed railway construction, ballastless track has been laid on a cross-sea cable-stayed bridge.
What does "ballastless track" mean?
There are two types of high-speed rail tracks: "ballasted" and "ballastless" tracks.
In contrast, the ballastless track has higher flatness and greater stability, and does not need to decelerate when passing the ballastless track, "like walking on the ground".
However, due to technical bottlenecks, ballast tracks are mostly used in domestic high-speed rail long-span bridges.
How can such a difficult technology be implemented in a difficult environment?
It is understood that the main girder of the bridge adopts effective aerodynamic measures to reduce wind-induced vibration, and the bridge deck adopts CRTS I double-block ballastless track.
In addition, a variety of sensors are installed in the main bridge section to monitor the bridge deformation data at different temperatures and different time periods, and the "relative elevation" measurement data is used to fine-tune the construction of the ballastless track, so as to overcome the ballastless track of the cross-sea cable-stayed bridge in one fell swoop. Measurement problems.
The laying of the track is only the first step. The lateral sway and vortex vibration caused by the sea breeze and the ruthless corrosion of the sea are all long-term tests.
Under the difficulty, heavy equipment was born.
The builders use domestic dampers to "anti-wind and stabilize", and set up an external damper and two built-in dampers on each stay cable of the main bridge of the bridge. When the stay cable encounters strong wind and generates high-frequency vibration , the damper can offset the vibration and ensure the stability of the stay cable; at the same time, the damper is also installed at the lower part of the steel girder of the main bridge to resist the rapid large displacement caused by the earthquake.
In order to ensure the long service life of the bridge, the steel anchor beams and supports of the pylons of the Fuxia High-speed Railway Anhaiwan Sea-crossing Bridge are made of marine and atmospheric corrosion-resistant steel, which can prevent the penetration of chloride ions in seawater and realize the long-term "rust-making". Effective anti-corrosion effect, filling the gap of my country's steel.
The closing site of the Anhaiwan Bridge on the Fuzhou-Xiamen high-speed railway.
Photo courtesy of Tie Siyuan
"One bridge, one policy", "Bridge Museum" has its own style
"The Fuxia high-speed railway is a bridge museum, and we have encountered various complex bridge types." said Wang Dezhi, the engineer in charge of the Fuxia high-speed railway at the Fourth Bridge Institute of China Railway Construction Corporation. Quanzhou Bay Bridge.
In July 2021, the Quanzhou Bay Bridge in Helong will have a total length of 20.3 kilometers and a main span of 400 meters.
It is not only the first cross-sea high-speed railway bridge in China, but also the world's first long-span cross-sea cable-stayed railway bridge with a speed of over 300 kilometers per hour.
The Quanzhou Bay Railway Bridge is next to a completed highway bridge, and the closest distance between the two bridges is only 28.7 meters.
The new bridge should be arranged opposite the old bridge as much as possible to make the water flow smoothly, reduce wind interference, and be more beautiful. Therefore, many conventional designs need to be broken through.
For example, it is the first time to use a non-supported integral bridge on a domestic railway bridge, and the main bridge of the railway bridge has chosen a "long-span" structure of 400 meters.
In addition, the approach bridge of Quanzhou Bay Cross-sea Bridge adopts double-block ballastless track, and the main bridge of the navigation hole adopts the polyurethane-cured track bed structure to "fix" the ballast for the first time on the cable-stayed bridge at home and abroad, which can effectively avoid the ballast track breaking under strong wind conditions. The ballast splashing endangered the safety of the train.
The ballast ran out of the "stunning" ballastless, ensuring that the high-speed rail can pass the bridge in 90 seconds.
The Meizhou Bay Sea-crossing Bridge is the first cable-stayed bridge with a low tower across the sea in China.
The "thousand-ton" mobile formwork set sail here, and the cast-in-place beam of the 40.6-meter large-span mobile formwork was first applied in the construction of high-speed rail.
The "Kunlun" 1,000-ton rack-transporting integrated machine constructed in the Meizhou Bay Bridge is the high-speed rail box girder laying equipment with the highest technology content, the most functions and the most extensive application scenarios in my country. It can adapt to minus 20 degrees to above zero. For construction operations in a 50-degree environment, the operating state can withstand the maximum wind force of level 7, and the non-operating state can withstand the maximum wind force of level 11.
The bridge erection machine integrates beam lifting, beam transport and beam erection, and has a high degree of intelligence.
The R&D personnel are equipped with a laser matrix sensing system for the equipment. By scanning the surrounding environment data, it can realize functions such as automatic driving in the tunnel and automatic deviation correction when walking, which can meet the construction operations of high-speed rail box girder with different spans of 24 meters, 32 meters and 40 meters. It is an "all-round equipment" in the field of high-speed railway bridge erecting machines.
"From the cross-river bridge to the cross-sea bridge, the high-speed railway bridge has already broken through the barrier between the river and the sea." Wang Dezhi introduced that the breakthrough in the technology of the Fuzhou-Xiamen high-speed railway in the cross-sea bridge is not only the transfer of the 350 km/h high-speed railway technology from the land to the sea, but also not only Only the span of the railway bridge from the river to the sea represents the leap in the quality of the railway bridge in my country, and plays an important role in promoting the future development.
Crossing mountains and mountains and crossing the sea, the grand scene of "China's World Marine Commerce and Trade Center in Song and Yuan Dynasties" reappears, and China's high-speed railway moves forward all the way.
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