Workers take over two years to drill just 156m ... and Yunnan tunnel is still not finished
Complicated conditions have hampered progress on what is seen as China’s most difficult tunnel project – it’s been under construction for nine years already
It’s been slow going for workers carving out a tunnel in mountainous southwest China – considered the country’s most difficult such project since it has taken some 26 months to drill just 156 metres, according to mainland media.
The 14.5km Dazhushan tunnel on a railway line linking Dali in Yunnan province with Ruili, a city on the border with Myanmar, has been under construction for nine years and it’s still not finished, news outlet Peoplerail.com reports.
The rail link crosses the Hengduan Mountains and more than 40 tunnels will have to be built. The geological and hydrogeological conditions around Dazhushan, in Yunnan, are complicated and staff have faced many difficulties to do with ventilation, transport, water and electricity in the process of building the tunnel, the report on Friday said.
Jiang Dong, a project manager with China Railway First Group, which is building the new line, said workers had to negotiate 12 faults in the landscape around Dazhushan and so far 10 of those had been completed.
Despite working around the clock it had taken 26 months to finish work on the most difficult of those faults, digging just 156 metres in that time.
More than 500 experts had been involved in finding a solution but they agreed there was no way to speed up progress. It was not clear when the Dazhushan tunnel would be completed.
Zeng Jing, who is with a local railway company and overseeing construction of the new line, said the extent of the difficulties had not been recognised when the project was approved. “We had planned to finish building the railway in 2014, but it now looks like it will be finished in 2021,” Zeng said.
It will take just seven minutes to pass through when it’s completed, the report said.