The error is 2 mm; the world's largest span high-speed railway ballastless track arch bridge is closed
"When the emperor died in the morning, he would return thousands of miles of Jiangling in a day." Li Bai wrote down a famous sentence for thousands of years near the city of Baidi, and the new mode of transportation will refresh faster. At 9:00 a.m. on October 30, the world's largest span ballastless track arch bridge of high-speed railway - the main arch of Meixi River double track super large bridge of Chongqing section of Zhengzhou Wanzhou high speed railway was successfully closed, which marked the important progress of the construction of Chongqing section of Zhengzhou Wanzhou high speed railway and laid the foundation for the smooth opening of the whole line. At that time, the high-speed railway with a speed of 350 kilometers per hour will be able to pass through the bridge in less than 10 seconds, while the fastest time for Chongqing to go to Beijing is only 8 hours
, the world's largest high-speed railway arch bridge with a span of 340 meters,
, connects Zhengzhou, Henan Province in the north and Wanzhou, Chongqing Province in the south, with a total length of 818 km and a designed driving speed of 350 km / h. It is the main high-speed passenger transport channel connecting North China, central China and southwest China. There are 27 tunnels and 32 bridges in Chongqing section. The ratio of bridges to tunnels is up to 98%. The terrain and geological conditions are complex and the construction is very difficult. Meixi River double track super major bridge constructed by Shanghai Engineering Bureau of China Railway is the key control project of Chongqing section of Zhengzhou Wanzhou high speed railway
"it is the most difficult to build Zhengzhou Wanzhou high speed railway in Chongqing, and this bridge is the most difficult in Chongqing." Wei Yanbo, project director of Meixi River Super Large Bridge of China Railway Shanghai Engineering Bureau, introduced that the bridge is located in Fengjie County, Chongqing City, and upstream of Meixi River Estuary, a tributary of the Yangtze River. The total length of the bridge is 687.8 meters. The main bridge is a rigid frame reinforced concrete through basket arch bridge with a span of 340 meters and a rise height of 74 meters. It is the largest high-speed railway ballastless track arch bridge in the world As a high-speed railway bridge,
has no 10 cm thick leveling layer, but the standard requires that the error of the whole bridge shall not exceed 10 mm, so how to ensure that the error does not exceed the standard is a complete test of "Craftsmanship". However, the location of Meixi River Bridge is steep on both sides of the bank, narrow construction site, and difficult to build access road. In addition, the bridge is located in the nature reserve of the Three Gorges Reservoir area, which has high requirements for water and soil conservation and environmental protection, so the construction organization is very difficult
in terms of mechanics, the faster the passing train speed is, the greater the bearing pressure on the long-span bridge is. To ensure that the high-speed railway with a design speed of 350 meters per hour does not slow down, the "foundation" and "strength" of the bridge must be ensured. Li Guohua, chief engineer of the project, said that the bearing platform, like the leg of a bridge, is the "foundation", but the steep slopes on both sides of the bridge are hard to stand. In this regard, they adopted the technology of horizontal pile and vertical pile separation embedded foundation for the first time in the construction of domestic high-speed railway bridges, making four 20.2-meter-long, 11.7-meter-wide and 14.18-meter-high commercial houses with horizontal cross-sectional area equivalent to two 120 square meters, and the bearing platform with concrete consumption of 2616 cubic meters firmly rooted A 6031 a 6031? A 6031 a 6031 cable lifts the last main arch from the ship. Li Zhi / figure
independently developed the intelligent monitoring system
to ensure that the closure error of the main arch does not exceed 2mm.
is the world's largest high-speed railway ballastless track arch bridge under construction. The main arch lifting and closure is the construction part of the Meixi River Super Bridge with the highest technical difficulty and the greatest safety risk The main arch of a 6031 a 6031 bridge is a steel arch rib encased concrete structure. The steel arch rib is equivalent to the "ribs" of the main arch, and the encased concrete is equivalent to the "flesh". During the construction, the arch rib is assembled first, then the concrete is pressed into the steel tube, and finally the concrete is poured outside the arch rib. Li Guohua said, "the key point of the construction of the main arch is to ensure that the 'steel ribs' are strong and firm."
steel arch rib is assembled from both ends to the middle. Due to the terrain, it can not be supported from the lower part, so it can only be lifted and buckled. This also makes the bridge involve more forces in all directions and the linear control more complex. The most difficult part of bridge construction is linear control
? "In the construction, we independently developed the intelligent monitoring system for hoisting in the arch." Li Ming, chief engineer of China Railway Shanghai Bureau Construction Co., Ltd., introduced that they collected the surface information with tilt photography technology, combined with BIM Technology, generated a three-dimensional model, and installed sensors in each part of the bridge, realizing the intelligent monitoring of the whole hoisting process. In the project department, the reporter saw that on the large screen of the monitoring platform, on the three-dimensional graphics of the bridge, the monitoring situation of each point corresponded to each other. Once there was a danger, it would immediately give an early warning, and the specific location was also clear at a glance The
project team divided the main arch into 48 hoisting units. In the splicing process, the construction technology of large-span cable buckle separation cable sling and large angle cable-stayed buckle was adopted for the first time in China. After scientific modeling, complex calculation, rigorous review, careful monitoring and repeated check of control parameters, the project team finally achieved the accurate assembly and smooth closure of the main arch, and the processing and assembly error was controlled within 2 mm, which was higher than the standard of 10 mm.