The Qinghai-Tibet Railway is laid on the plateau at an average altitude of 4500 meters, due to the high altitude, the year-round temperature is very low, under the roadbed is a layer of permafrost for many years, and in some places the permafrost layer is as thick as more than 20 meters; these permafrost will melt and fall in the warm season, and freeze and expand in the cold season, and this together with a fall will seriously affect the stability of the railroad roadbed. The Qinghai-Tibet Railway passes through 550 kilometers of such permafrost, which is half of the total length of the railroad!
In the construction of the project, the zone has adopted a localized method: the relatively stable permafrost section to take the schist ventilated roadbed, schist guarding the roadway, hot rod technology, laying insulation board and other methods, so that the roadbed ventilation, accelerate the heat emission, reduce the temperature, maintain the stability of permafrost. For the extremely unstable permafrost section, the method of "bridge instead of road" is adopted, that is to say, the bridge is used instead of the roadbed. Bridge project using pile foundation, each pier below four pile foundation, each pile foundation to go deep underground more than 20 meters, pouring concrete piers after the point and different geological conditions, to take the waterproof lining insulation layer, slurry retaining wall and other effective measures to overcome a series of construction problems. At present, China's scientific research in the field of railroad permafrost has been at the forefront of the world, but also the birth of a number of permafrost research of the new force.
II. Ecological fragility
The Qinghai-Tibetan plateau has a cold climate, large temperature difference between day and night, the soil layer is shallow and infertile, the ecology is very fragile, but suffered from man-made damage, to recover almost impossible. To this end, the qinghai-tibet railroad construction project for the first time made the environmental protection and construction of the same important commitment, and signed with the local government environmental protection agreement; railroad construction project for environmental protection is expected to amount to more than 2 billion yuan, accounting for about 10% of the total investment in the project, environmental protection investment and accounted for such a large proportion of the first in the history of domestic construction.
Environmental awareness and action everywhere: in the pile construction, the engineering staff creative application of rotary drilling rig dry hole this new environmentally friendly construction technology, it can be quickly into the hole, not too much interference with the permafrost layer, but also will not pollute the environment. Coco Sicily is a national nature reserve, the railroad through here, the construction of the Qingshui River Bridge, which is the longest "bridge instead of road" project, but also the Qinghai-Tibet Railway specifically for the Tibetan antelope and other wildlife migration and open up the channel. For the unavoidable environmental damage during the construction process, artificial grass planting and turf transplantation methods are adopted to maximize the restoration of vegetation. Since the start of the project, the tundra environment along the railroad and the water quality of rivers and lakes have not changed significantly, and wild animals migrate freely, which is extremely effective in protecting the wetland ecology.
III. Cold and lack of oxygen
Low temperature and thin air on the plateau, this special climatic condition is a severe test for construction personnel and construction equipment. During the construction, the engineers used their own invented technology to strengthen the low-temperature-resistant performance of the electrical system, improve the oxygen supply of the power system, and turn these equipments into the most advanced plateau engineering equipments in the world.
In terms of construction personnel, the Ministry of Railways and the Ministry of Health jointly issued a document for the first time to make detailed and specific provisions for medical and health care, and invested 200 million yuan to build a three-tier medical care system covering the entire line, so that personnel suffering from severe altitude sickness and plateau disease could be treated in time, and over the past two years of construction, the company has realized the "three no's" of zero deaths from altitude sickness, zero occurrence of SARS, and zero spread of bubonic plague. The "three noes" goal.