How to repair the most difficult railway from the basin to the roof of the world?

Sichuan-tibet railway, from the Sichuan Basin to the Qinghai-Tibet Plateau, has a harsh geographical environment and a large terrain gap, so it is very difficult to build roads. The height difference of the whole line is more than 3000 meters, and the accumulated climbing altitude mileage is1.4000 meters.

There is such a railway, which started in the early days of the founding of New China, and began to select the line in the 1990s, and it was not until two years ago that construction really started. This is sichuan-tibet railway, bearing the dreams of generations.

Sichuan-tibet railway is called "the most difficult railway to build". Sichuan-tibet railway is100km shorter than Tianlu Qinghai-Tibet Railway, but its construction period is longer and its investment is several times.

Today, the most difficult section of sichuan-tibet railway-Kangding (xinduqiao) to Linzhi section has entered the design stage. In order to promote the railway construction in sichuan-tibet railway and complex and dangerous mountainous areas, 18 held a high-level academic exchange meeting in Chengdu on June 4, 2008, and 14 experts, including 8 academicians, gathered together to discuss the challenges and countermeasures of sichuan-tibet railway's construction.

How hard is it? Climb more than 2000 meters in 50 kilometers

At the academic seminar, Sun Yongfu, chairman of China Railway Society and academician of China Academy of Engineering, said: "sichuan-tibet railway has crossed five terrain areas." This is also the most complex terrain in the world.

From 195 1, according to the arrangement of China Railway Corporation (formerly the Ministry of Railways), China Railway Second Institute has been carrying out survey, design and related research in sichuan-tibet railway. Zhu Ying, general manager of the Institute, said that the construction of sichuan-tibet railway needs to face four major environmental challenges: obvious terrain elevation difference, strong plate activity, frequent mountain disasters and fragile ecological environment.

Lin, deputy chief engineer of China Railway Second Hospital and general manager of sichuan-tibet railway Survey and Design, said that the highest elevation of the railway is 4,400 meters, with a height difference of more than 3,000 meters. For example, from Luding to Kangding, just after crossing the Dadu River, we have to climb many mountains. The straight-line distance is only 50 kilometers, but the altitude difference exceeds 2000 meters, which is equivalent to climbing 50 meters per kilometer. The railway can't climb on such a straight slope.

How to choose the line? Conduct more than 50 studies at the same time.

Lin recalled that only the route from Kangding to Basu needed to cross the Hengduan Mountains, and three routes were put forward in the early days. Comprehensive comparison of topography and geology, analysis of the advantages and disadvantages of earthquake disasters, consideration of economic strongholds and comprehensive transportation, finally chose the plan of Manager Tang and Changdu.

Rockburst, aeolian sand, gravel road, canyon wind, seasonal frozen soil ... Zhu Ying introduced that in view of the above difficulties, the route selection of sichuan-tibet railway not only considered the construction practice, but also considered the operation safety and later maintenance. Under the guidance of the concept of "route selection for disaster reduction", more than 50 studies were conducted simultaneously.

How to break it? Through "line extension"

In order to solve the problem of short distance and large drop, the railway is realized by "laying lines". For example, Lin said that the line from Luding to Kangding is Z-shaped, with a total length of115km, which is twice as long as the straight line. The maximum design slope is the largest slope in China at present, and climbing is realized by strengthening the power through double-machine traction.

Unlike the "gentle slope" of the Qinghai-Tibet Plateau, sichuan-tibet railway is "stepped". From Chengdu to Lhasa, the accumulated climbing altitude mileage reached 1.4 million meters.

In order to eliminate the obvious terrain elevation difference, sichuan-tibet railway mostly adopts Gao Qiao and tunnel, and the bridge-tunnel ratio is 865,438+0%.

Basu Nujiang Bridge has a total length of 1.300 meters, a main span of 1.064 meters, and a height from foundation to deck of 70 1 meter. "When the bridge reaches this height, it can be connected with the rising railway."

The length of Haizishan Tunnel, Mangkangshan Tunnel and Boshula Tunnel is close to or more than 30 kilometers. According to Lin, judging from the Wenchuan earthquake, the tunnel is relatively safe in the earthquake zone because of the mountain swing, which is one of the reasons why tunnels are often used in design.