Trial by water
The Hanjiang-to-Weihe River water diversion project is full of challenges. Geological disasters such as fault landslides, rock bursts, hard rocks, water inrush, and harmful gases often occur during the construction of the water tunnels in Qinling Mountains.
The comprehensive difficulty is unprecedented in the world and constantly refreshes national record. When the underground river is dug to cause serious water inrush, the amount of water flowing out of the tunnel in a day is enough for the population of a medium-sized county. The rock at the southern foot of the Qinling Mountains is harder than the steel plate, and the tunnel borer usually encounters a rock burst every two meters on average.
In the course of the project, workers once encountered strong water inrush of 46,000 cubic meters a day. As the temperature inside the cave exceeds 40 C, the rock would become very hard and the tunnel borer seems to drill on a steel plate. Emergency holes are built to prevent the tunnel construction from flood. Quality inspection was controlled in the highest standard.
