AECOM’s innovative scheme of immersed tunnel methodology continues to break ground to diversify our business portfolios in China, growing the market penetrating deeper while relieving traffic congestion for some of the country’s most populous cities.

In order to alleviate the traffic congestion in the downtown area of Guangzhou, one of China’s most populous cities, a new immersed tunnel needed to be built beneath Pearl River to connect Haizhu District and Fangcun District. AECOM proposed an innovative scheme of immersed tunnel methodology for overcoming engineering constraints.

AECOM specialized expertise in immersed tunnel, marine works, geotechnical and traffic engineering collaborated to deliver the most cost-effective solution, particularly with several innovations developed in this project. These innovations include recommending shallower immersed tunnel option of shorter approach tunnel sections instead of deeper TBM bored tunnel or bridge schemes to resolve land issues in both banks for the approach tunnel section, avoiding problems of land acquisition and minimize the project’s budget and schedule.

Further, given the geological limitations on site, the design plan constructed the dry dock in line with the tunnel approach at the edge of the river bank to keep the transportation route for the tunnel units very short and the amount of dredging of Pearl River limited. And in order to allow the additional climbing lane of traffic insider the immersed tunnel element, a tapered shape immersed tunnel elements were proposed for the first time of use in China to address imbalanced hydrostatic force during floating, towing and sinking operations. With AECOM’s expertise, detailed calculation and assessment, the tapered unit scheme was successfully constructed, floated, towed and completed installation.