China builds first high-speed railway through karst region

 Construction of China's first high-speed railway running through the country's southwest karst regions was completed on Sunday.
The 857-km railway linking Guiyang, capital of landlocked mountainous province of Guizhou, with south China's economic powerhouse Guangzhou, is expected to become operational on Friday.
Guizhou has the world's most typical karst plateau landscape, which was inducted as a UNESCO World Heritage Site in 2007. Karst topography is a landscape formed from the dissolution of soluble rocks such as limestone.
Stretching through the complicated karst clusters, the railway had half of its length run through 238 tunnels, two of which are more than 14 km long, said Zhang Jianbo, general manager of the Guiyang-Guangzhou High-Speed Railway Co.
It took builders four years to drill through the two longest tunnels. Construction was often disrupted by breaking rocks, rupture of strata and water infiltration, Zhang said.
The construction company applied for six national patents covering their shockproof technology which was adopted to reduce the vibration that occurs when a train travelling at 250 km/hour runs through mountain tunnels.
Wang Mengshu, a tunnel expert with the Chinese Academy of Engineering, said the technology and machinery engineering developed for building the Guiyang-Guangzhou high-speed railway represents the country's new-generation innovation in tunnel engineering.