The blueprint of the ambitious project is expected to be submitted to the State Council of the People's Republic of China in April, the China Daily reported on Friday.

"Once approved, work could begin as early as 2015 or 2016," said Wang Mengshu, a tunnel and railway expert at the Chinese Academy of Engineering, who has worked on the plan since 2012.

Wang said that the 123-km underwater tunnel will cost around 220 billion yuan (USD 36 billion).

The length of the tunnel will be more than the combined length of the world's two longest underwater tunnels - Japan's Seikan Tunnel and the Channel Tunnel between Britain and France.

"Using the tunnel, it will take only 40 minutes to travel from Dalian to Yantai," Wang said.

At the moment, it is a 1,400-km drive and it takes eight hours by ferry.

Wang, however, emphasized that the safety of the project will be the top concern.

"The draft plan has two chapters discussing the potential dangers in the project and the emergency plan," he said.

Wang's colleague Tan Guangzhong said flooding is the biggest safety risk during tunnel construction.

He said, during the construction of the Seikan Tunnel, a slew of leaks led to financial losses and killed four workers.

Wang said the Bohai tunnel will be built at least 30 metres below the seabed, which is mostly hard rock.


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