Nerves are taut in China over the structural integrity of the Great Wall at Badaling as engineers blast a tunnel deep underneath for a record-breaking high-speed railway, and a cavernous station.
The 12-km-long tunnel will sink to a maximum depth of 432 meters under the most visited section of China’s Great Wall, completed in 1504, to carry a trains running at 350km/h between Beijing and the city of Zhangjiakou ahead of the 2022 Winter Olympics, which the two cities are co-hosting.
The project’s chief engineer Luo Duhao said precision micro-blasting has a velocity of 0.2cm per second and generates a weaker tremor than traditional blasting.
Since February there have been 4,500 blasts.
It took Chinese engineers months to “choreograph” the best point for the 174-km Beijing-Zhangjiakou High-Speed Railway Line to intersect the Great Wall.
When complete in 2019, the railway is expected to cut the journey time between the two cities from more than 3 hours to around 1 hour.
As well as the tunnel, engineers are building a large station 102m underneath the Great Wall. The station is reported to be 36,000 sq m in area.
Dai Longzhen said the construction area and the depth of the station is “record-breaking”.