Daunting tunnel broken through to Hengqin, but wait

The Maliuzhou Tunnel beneath Gongbei and the sea was finally linked end-to-end on Nov 13. Drilled by a super-diameter machine in difficult compound strata, the subterranean and subsea route from the Hong Kong-Zhuhai-Macao Bridge to Hengqin New Area is to be completed next summer, according to Shanghai Tunnel Engineering.

The 2,834-m six lanes passing under the Maliuzhou Waterway will be the third roadway to the New Area from downtown Zhuhai after the Hengqin and Second Hengqin bridges.

Construction began in July 2014 when the grand-shield tunneling machine worth 400 million yuan ($60 million) roared to life. The tool is about five stories high and more than 100 m long. It weighs over 3,000 tons and has a diameter of 14.9 m.

Run-through of Maliuzhou Tunnel

In addition to riprap, rock stratum, and drainage, engineers had to deal with excessive sediments caused by frequently changing seabed rock conditions. Intricate geological structures are common throughout South China, according to a senior engineer.

Overcoming those difficulties, the run-through has modeled practices to be followed in similar projects requiring underground space development in the region. For example, multiple hi-tech techniques such as millisecond blasting and undersea reinforcement measures ensured precision and successful clearing.

The large-scale municipal project is being managed by Zhuhai Da Hengqin Port Industrial Co Ltd. Groundbreaking and excavation cost the Hengqin New Area Administrative Committee 2.5 billion yuan ($376 million). 

Tunneling monster [Photos by Zeng Yao / Zhuhai Daily]