Recently, when the Qinghai-Tibet Railway will firstly meet the winter, someone began to worry whether the railway facilities and train in the pergelisol zone would be able to withstand the test of a severe winter. For this issue, some media interviewed NCC experts. The NCC experts pointed out that Qinghai-Tibet Railway construction experts had given full consideration to the climate change impacts, a certain degree of security had been reserved, and adopted variety measures to strengthen the pergelisol protection. Thus, there seems to be no problem to keep the railway safe and smooth.
The Qinghai-Tibet Plateau is the world's highest and largest pergelisol area in low latitude, the pergelisol area is 70% of China’s total pergelisol. In winter, the pergelisol activities layer is freezing like ice and its volume is expanded, causing the above sub grade and rail to uplift. In summer, the volume of pergelisol activities layer became narrowed, and the sub grade and rail will be depressed. The freezing and thawing of pergelisol iterative, the sub grade will be frothing, and the rail will be up and down in wave-shaped, it will influence the safety of railway operation.
The Global warming brings a huge influence on the pergelisol of Qinghai-Tibet plateau. From 1970s to 1990s, the temperature of seasonal pergelisol, financial and island pergelisol zone along Qinghai-Tibet Railway have rise 0.3-0.5 degrees, and the average temperature of continuous pergelisol zone have rise of 0.1-0.3 degrees. Nearly 10,000 square kilometers of plateau pergelisol area may reduce in the recently 30 years. In the next 30-50 years, the pergelisol environment along the Qinghai-Tibet Railway will be very sensitive on climate change. In other words, the global warming will influence the safety of railway operation and the road.
Such a world famous project as the Qinghai-Tibet Railway, the railway experts considered the climate experts’ prediction, made reference to other countries’ similar experiences in high latitude, and carried out variety measures to protect the pergelisol, in order to improve the stability of sub grade. In the construction of the world's highest and longest pergelisol tunnel, Chinese scientists had captured more than 20 construction problems of plateau pergelisol. Many measures are domestic and foreign initiative. Qinghai-Tibet Railway is a world pergelisol project museum.
Prof. Zhang Luxin, the head of the Advisory Group of Qinghai-Tibet Railway Construction, said we must have a scientific attitude to deal with the technical problems in the construction of Qinghai-Tibet Railway, we had set up a long-term monitoring system to understand the temperature changes of typical lot pergelisol zone, and access the temperature change characteristic data that before and after the railways construction. He said that the possibility of a large-scale Pergelisol Project Disease of Qinghai-Tibet Railway is low, and there might be no problem to maintain the annual operation.
