Chinese engineers digging world’s longest tunnel in Xinjiang desert hit a wall – of gushing water
- Work on tunnels to introduce snowmelt to arid region disrupted several times by ‘water inrush accidents’, paper by project engineers says
- Apart from the risk of damage to costly boring machines, such incidents threaten to seriously affect construction schedule
Chinese workers building what would be the world’s longest tunnel have come up against an unexpected problem in one of the driest areas on Earth – gushing streams of water.
“High groundwater levels have caused frequent water inrush accidents that seriously affected the construction schedule,” said Deng Mingjiang, a professor with the Chinese Academy of Engineering, in a paper published in domestic peer-reviewed journal Tunnel Construction last month.
Kashuang tunnel, the longest of the three mega tunnels in the project, is expected to stretch for 280km (174 miles), more than twice as long as the Delaware Aqueduct – the main water supply tunnel of New York City – which has held the record since 1945.
But from time to time, the tunnel boring machines (TBMs) run into an unusually rich groundwater source that bursts out so forcefully that it could fill a swimming pool in an hour.
Every time the flooding alarm flashed red, the report said, workers would need to evacuate and the giant boring machine would be made to stop and pull back immediately or risk serious damage.