On January 28, the final base slab of the Nanquan section of the Taihu Tunnel, the longest underwater tunnel currently under construction in China, was poured, marking another phased milestone in the main structure construction of the Taihu Tunnel.

As a key controlling project of the Suzhou-Wuxi-Changzhou South Expressway, the 10.79-kilometer Taihu Tunnel has attracted widespread attention from all sectors.

Cofferdam construction method

The Taihu Tunnel adopts the cofferdam construction method, advancing section by section from the shore into the lake. After the sequential completion of cofferdam construction, water pumping and dredging, bored pile construction, foundation pit excavation, cushion layer construction, waterproof layer installation, and base slab rebar tying, the first layer of main structure construction begins.

Base slab pouring

As an important part of the main structure construction of the Taihu Tunnel, each base slab section is 20 to 30 meters long and 43.4 meters wide, with approximately 1,900 cubic meters of concrete poured per section.

On July 30, 2018, the first base slab on the Nanquan side of the Taihu Tunnel, constructed by the CX-WX3 section of the Suzhou-Wuxi-Changzhou South Expressway under China Railway No. 4 Engineering Group, was officially poured. After two and a half years, the full 5.38 kilometers of tunnel base slab has been completed.

About the Mashan section

The Taihu Tunnel is divided into the Nanquan and Mashan sections. At present, the cofferdam and earthwork excavation of the Mashan section have been fully completed. The cumulative completion of the tunnel main base slab is 4,815 m, with 597 m remaining, accounting for 74.2% of the total design length of 5,412 m. The cumulative completion of the roof slab is 3,710 m, with 1,530 m remaining, accounting for 60.1% of the total design length of 5,210 m.

The Suzhou-Wuxi-Changzhou South Expressway is an important component of the Jiangsu expressway network. It starts in Qianhuang Town, Wujin District, Changzhou, and ends in Nanquan Town, Wuxi, connecting to the Wuxi Ring Taihu Expressway, with a total length of 43.9 kilometers.

Upon completion, the project will add a new expressway corridor between Shanghai and Nanjing, which is of great significance for promoting the development of Suzhou, Wuxi, and Changzhou cities along the route and accelerating the integration of the Yangtze River Delta.