China completes challenging track-doubling project

[John Ashworth]

China completes challenging track-doubling project

CHINA National Railway (CR) has completed a technically challenging project to rebuild a 68km section of the Chengdu – Kunming railway.

The rebuilt 160km/h double-track line links Miyi with Panzhihua and passes through very difficult terrain. The project required the construction of 13 tunnels with a total length of 55km and 18 bridges totalling 5.56km.

The 12.4km-long Yakou tunnel traverses six sets of strata and seven regional faults. The 12.76km Ranjiawan tunnel passes through the unique Xigeda stratum in the Panxi area. The stratum can disintegrate easily after being immersed in water.

The project also faced numerous obstacles, including large surface structures beneath the 186 million m3 Majiatian tailings reservoir, high-rise buildings in residential areas, and a large artificial lake in Huacheng New District, the bottom of which is only 5m above the top of a tunnel, which made the design and construction extremely difficult...