The most difficult construction in China, the railway should be opened today

The Yi-Wan railway was opened to Operation today. The railway is widely concerned because of its difficulty in engineering and long construction period. Why the Yi million railway is called the history of the construction of the most difficult railway? Why did the technicians give up the railway line of "stranded" in the late Qing Dynasty? Why does the Yi-Wan railway not "speed up" in today's high-speed rail? Is it safe to travel by train, with complex geology along the railway?　　Iron Four courtyard of several railway experts on the focus of attention to all sectors of the answer. Why the construction of the most difficult line length of 377 kilometers of the Yi million railway, east of Yichang, Hubei province, west to Chongqing Wanxian District. From 2004 all started to be opened to traffic now, consumption of 50,000 railway builders 7 years, the annual progress of only 50 kilometers, is China's single kilometer construction of the longest railway.　　What is the reason for this railway to take so long? Yi-Wan Railway is the most difficult mountain railway in the history of engineering.　　"Yi million railway overall design director Hu Ziping said. According to the introduction, Yi million Railway "difficult" is not difficult in its line of 74% for the bridge and tunnel, but difficult in the karst landscape blend. The main stream and tributaries of the Yangtze River will erode the mountains into many deep valleys. Beneath the surface, after billions of years of water flow, numerous strange caves and river systems have been developed, this is the hands of the natural wonders of heaven, God of Creation of the magic Scroll, but for the construction of this area in the next step of the murder, slightly inattentive, river in the water will roar out;　　The rock wall in the cave collapses. Water inrush, mud bursting, karst, collapse ...　　Many geological risks become a "stumbling block" in construction. The degree of risk, scale and difficulty of engineering treatment of Yi-Wan railway are rare in the world, especially in karst tunnels, which is called a world-class problem by many academicians and experts in engineering field. For example, the elevation of nearly 1500 meters of Qiyueshan, beautiful appearance, but in which the tunnel construction is dangerous. Qiyueshan Tunnel in the construction has been found in 150 dissolved cavities, surrounded by 3 river system, all kinds of sinkholes, shafts, water caves, tap points dotted. Here the groundwater is abundant, the pressure is extremely high, once the water flow releases, can easily spray on hundred storeys tall building. The tunnel started with a total of 63 million cubic metres of water, equivalent to the evacuation of a large reservoir. "If you want to zhunbing in the cave, a big cave can zhunbing a division." "Deputy Chief Engineer Miodehei image description.　　The tunnel took nearly 5 years to advance more than 3,000 meters, creating its own "slowest record". Hu Ziping said: "In addition to geological complex, difficult to build, the extension of the construction of the Yi-Wan railway is also a reason, that is, the railway Yichang to cool fog section originally for single line design, 2006, according to the need to change to double track." Why give up the early design line it is understood that the late Qing Dynasty Zhan Tianyou was commissioned to build the Sichuan-Han railway, the choice along the long Jiangbei bank through. In the early 60, Mao Zedong, Zhou Enlai and other older leaders have planned to build the Sichuan-Han railway, the choice is also along the river plan. From Zhan Tianyou to the early days of the founding of the New China Railway workers,Although they are all Chungzhi, the accumulated experience and information is still valuable.　　So why did the Yi-Wan railway give up its early design line and "reinvent itself"? Hu Ziping said that the Yi-Wan railway at that time had launched three major options for selection: The first is along Qingjiang, from Yichang, by Enshi, Lichuan to Wanxian; the second is along the Yangtze River Project, from Yichang, through Zigui, Fengjie to Wanxian; the third option is the current construction program-"The Ridge line", selected through the Yangtze River and Qingjiang between the Wuling Mountain, All the way through the mountain ridge, since Yichang, by Enshi, Lichuan to Wanxian.　　Of the three scenarios, the two most controversial are the latter. Hu Ziping explained that along the Yangtze River North bank scheme mainly has several major drawbacks: first, the line topography and geological conditions are equally complex, difficult to construct; the second is the remote town, the surrounding city economic pull is not obvious, three is to destroy the Yangtze River, Qingjiang water, not conducive to environmental protection.　　Therefore, the comprehensive comparison, the "ridge line" more economical and applicable. Why the Yi-Wan railway does not "speed up" Yi Wan railway east from Hubei province Yichang, west to Chongqing Wanxian District, length of 377 kilometers. Among them, Yichang Dongzhi cool fog section 288 kilometers for two lines, design speed 160 kilometers, cool fog to Wanxian section 89 kilometers for single line, design speed of 120 kilometers.　　In today's high-speed railway, why does the Yi-Wan railway not "speed up"? Hu Ziping explained that high-speed railway is mainly used for passenger dedicated lines, more in the economic conditions, the network has a dense area. The Yi-Wan railway belongs to the passenger and freight mixed transportation line.　　Towns along the line are not dense, the economy is not developed, the population is also relatively scarce, the use of existing standards both economically and fully meet the actual needs. Whether the Yi-Wan railway is safe or not, the railway is located in the combination of Yunnan-Guizhou plateau and the middle and lower reaches of the Yangtze River. Is it safe to operate in such a complex geological area? "Security issues can be assured. After the completion of the railway, experts have been divided into 6 groups have a number of hidden dangers along the road for several dragnet.　　The expert replied.　　Experts introduced, Yi million railway transport safety technology research and process design are domestic initiative, some of the topics in the forefront of international technology. For example, in dealing with complex geology, using the latest technology of aerial photography and Global Positioning System (GPS), such as real-time dynamic positioning, large scale aerial photography and other advanced technologies, using ultrasonic physical detection technology to detect the nature of deep strata in the ground floor.　　Through advanced measurement and exploration methods, the major engineering such as landslide, river and so on, the hydrogeological and the problems affecting the safety of tunnel construction and the complicated geologic background, forming law and controlling factors of inducing geologic hazard are basically identified. In the construction of tunnels, the research on the type and construction method of supporting structure under the condition of high pressure has been carried out. For example, for tunnels through the large caves, engineers used 26 reinforced concrete pillars to the surrounding cave to be fixed, and the upper layer of the cave to build a double frame lining structure to stabilize the cave, which is like the top of the cave installed "ceiling"The same. Under the "ceiling" is the train passage, under the train is the bottom of the cave is done pile Foundation reinforcement.　　Therefore, the train is very safe when passing through the tunnel. This newspaper comprehensive news Tian Feng drawing Shanghai Han Rong Big channel two years after the opening of the Yi million railway, reporters from the Yi-million railway operation Map found that Wuhan to Sichuan and Chongqing time is not shortened, still need about 18 hours. Prior to this, the relevant departments said, after the opening of the Yi-million railway, Wuhan to Chongqing, Chengdu Time will be greatly shortened.　　Why is time almost unchanged? Wuhan Railway Department said that at present, Wuchang to Chongqing North K1024/1 train through the Handan line, Xiang-Yu line, the whole 1226 kilometers, it takes 18 hours 58 minutes.　　Starting January 11 next year, the train to take the long Jing Line, Yi million line, the kilometer reduced to 1136 km, the whole need 17 hours and 6 minutes, than currently only shortened 1 hours and 52 minutes. Wuhan-Chengdu T250/1 Times, at present through the Handan, Xiang Yu, reached the line, the whole 1369 kilometers, it takes 18 hours 36 minutes.　　Starting January 11 next year, the train to take the long Jing Line, Yi million line, Tatsu million lines, mileage shortened to 1268 kilometers, but the whole process takes 19 hours 25 minutes, than the original extension of 49 minutes. Wuhan Railway Department said, as Wuhan to Yichang Long Jing Railway is still a single line, and the quality of the circuit is not high, only about 60 kilometers per hour.　　And the Yi million railway cool fog to Wanxian 88.54 kilometers, is also a one-way design, the highest speed of only 120 kilometers, Wanxian to Chongqing, Wanxian to Chengdu, the railway speed is not high, therefore, by both ends of the railway speed limit, resulting in Wuhan to Sichuan and Chongqing can not speed up. The railway department introduced that after the opening of the Han-Yi Railway next year, Wuhan to Yichang will be shortened from the current 5 hours to 1.5 hours. Lichuan to Chongqing's Yu-Li Railway in 2012 after the opening of the Shanghai-Han Rong Railway channel will be completely through, within 5 hours from Wuhan arrived in Chongqing. Cheng-yu area to Shanghai can realize Chiva, "Shu Road difficult" history will change from now on.