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Original title: [New Era, New Journey, New Achievement, High-quality Development Research Tour] Sichuan-Qinghai Railway Construction Accelerated - Visiting the Construction Site of Key Projects①

Qinghai News Network·Beautiful Qinghai Client News In early autumn, the plateau is picturesque. The Jianzha Yellow River Bridge of the Sichuan-Qinghai Railway, located at the junction of Jianzha County, Huangnan Tibetan Autonomous Prefecture and Hualong Hui Autonomous County, Haidong City, is under intensive construction.

The construction site of Jianzha Yellow River Bridge. This span makes this bridge the world's largest double-track railway continuous steel truss arch bridge. Photo: Ni Xiaoying Dong Jie

The construction site of Jianzha Yellow River Bridge. This span makes this bridge the world's largest double-track railway continuous steel truss arch bridge. Photo: Ni Xiaoying Dong Jie

The construction site of Jianzha Yellow River Bridge. This span makes this bridge the world's largest double-track railway continuous steel truss arch bridge. Photo: Ni Xiaoying Dong Jie

"Raise the hook, to the left... the hook stops... the hook drops..." On August 24, at the steel beam construction site on the north bank of the Jianzha Yellow River Bridge of the China Railway Major Bridge Engineering Bureau of the Sichuan-Qinghai Railway, Master Zhou Lijun, who was in charge of the hoisting, communicated with the arch hoisting driver through the intercom, and cooperated with three or four workers to hoist the stiffening chord of the lower chord Z-1 of the 10th interval to the designated position using a 70-ton fully revolving mast crane.

Although it is already autumn, the scorching sun can still be felt on the plateau, and the workers' skin is getting darker and darker. "The heat conductivity of steel beams is good, and the temperature rises quickly, especially in July and August. Sometimes the hoisting time is not right, and we have to rush to drive nails at noon. If the gloves are not worn properly and touch the surface of the steel beam, it will be burned by the teppanyaki." After the rods were aligned, Master Zhou took a breath and relaxed his serious expression just now, and chatted with the reporter humorously.

Standing on the steel beam and looking out, the famous Angla White Pagoda in Jianzha County stands on the right side of the bridge line not far away. The white and green complement each other, creating a unique artistic conception. In response to this, the busy figures of workers are installing guardrails on the bridge deck, some are wearing masks to weld on the bridge deck, and some are wearing safety belts and helmets to drive nails... The project is proceeding in an orderly manner. In the future, a railway steel arch bridge will cross the Yellow River, integrating with the mountains and rivers here and benefiting the people.

"The Jianzha Yellow River Bridge has a total length of 1,596.2 meters, of which the main bridge is a three-span continuous steel truss tie-arch bridge of 141 meters + 366 meters + 141 meters, with a total length of 648 meters. It crosses the Yellow River in one span and is currently the world's largest span double-track railway continuous steel truss arch bridge. It is also the first railway steel truss arch bridge across the Yellow River in my country." Zhu Xuan, deputy chief engineer of the Sichuan-Qinghai Railway China Railway Major Bridge Engineering Bureau project department, said proudly.

This railway bridge is indeed unique. The reporter found that there were no bridge piers in the water. Zhu Xuan explained that the original design span of the bridge was only 350 meters. At that time, half of the main pier No. 28 on the north bank was in the Yellow River. Considering that the area is located in the National Aquatic Germplasm Resources Protection Zone for Unique Fish in Jianzha Section of the Yellow River, including rare species such as the plateau loach, the naked schizont fish of the Yellow River, and the polar flat-throated fish, the design was changed to a main span of 366 meters at that time, crossing the Yellow River in one go, reducing the interference of water construction on the reproduction of special fish and further protecting the diversity of species in the Yellow River Basin.

At the same time, the project department also changed the original "arch first, beam later" plan of transporting beams from the dock to an "arch and beam synchronous" erection plan. In this way, the on-site construction is basically completely isolated from the Yellow River, and will not have any impact on the Yellow River water resources and the country's special fish species.

In order to ensure the smooth progress of the erection of the steel truss of the bridge, a lot of "high-tech" was used on site. Before the erection, a BIM information model of the steel truss arch bridge was established. By performing three-dimensional digital measurement on the segments, a three-dimensional reverse model of the rods was constructed to check and analyze the machining accuracy of the rods and node plates. At the same time, virtual pre-assembly technology was used to effectively foresee possible assembly errors during the actual assembly process. The reverse digital model was also used to adjust parameters such as the axis, elevation and torsion deviation of the relevant segments, and to make necessary corrections to the segment assembly points, thereby effectively reducing the overall assembly error and achieving high-precision linear control.

"The precise positioning of these rods requires our surveying team to go out at night," said Sun Zaiming, the person in charge of on-site measurement. "Due to the influence of light and temperature during the day, the expansion and contraction of the beams on the sunny and shady sides are different, and the measurement values ​​are inaccurate, which will affect the measurement accuracy. Therefore, the final positioning measurement is selected after 23:00. We set up an independent measurement control network around the bridge. Each internode has four positioning observation points. We use the Leica intelligent robot TS30 for repeated measurements and perform deviation analysis on the large amount of collected data. Sometimes a measurement takes a whole night." From the upward raised corners of Sun Zaiming's mouth, it can be seen that he is very good at how to control the accuracy of bridge erection with high precision, and he is confident.

As an important part of the Lanzhou-Guangzhou corridor of the national "eight vertical and eight horizontal" high-speed rail network, the Sichuan-Qinghai Railway is also one of the fast railway corridors in western my country. After completion, it will not only play a huge role in promoting the economic development of the areas along the line, but will also greatly improve the travel conditions of the people. It is of great significance to strengthen the connection between the two major economic belts of the "Silk Road Economic Belt" and the "Yangtze River Economic Belt" and implement the new era of western development strategy.

"Currently, the bridge is in the stage of erecting steel truss arches. The main bridge is designed with 50 sections. The north bank has been erected to the 10th section, and the south bank has been erected to the 7th section. It is expected that the main bridge will be completed in July 2025." Zhu Xuan said that the project construction has always adhered to the bottom line of safety and quality first, and promoted the construction of this project with the spirit of pursuing excellence and continuous improvement, striving to create a high-quality project that can stand the test of history.

They build roads through mountains and bridges over rivers. Reporters on the scene could truly feel that although the bridge builders had different divisions of labor, they had the same goal, and everyone was proud to be able to participate in the construction of this world-class bridge.

On the way back to the project site, the sun had already set, and a large area of ​​​​fiery red clouds ignited in the sky, like thousands of red flags fluttering. Looking back, the Jianzha Yellow River Bridge under construction was like a huge "sky bow", and the Yellow River was like a "magic arrow", standing in the sky ready to be launched.

(Ni Xiaoying)

(Qinghai Daily)