Tunnelling has been completed on China’s Tianshan Shengli Tunnel, said to be the world’s longest expressway tunnel.
The 22.13km tunnel through the Tianshan Mountains is part of a new north-south link in the Xinjiang Uygur Autonomous Region.
It is a key project of the Urumqi-Yuli Expressway, which runs from the regional capital of Urumqi in northern Xinjiang to Yuli County in southern Xinjiang. The expressway, which will provide an alternative to the existing weather-prone, winding mountain roads, is expected to open to traffic this year. The new road will reduce journey times from about seven hours to just over three hours.
Tunnel construction began in April 2020 and has faced challenges such as extreme cold, high altitudes, high ground stress, strong seismic activity and strict environmental requirements.
The Tianshan Mountains are known as a “geological museum”, featuring numerous fault zones, 16 of which the tunnel passes through. Its No. 2 ventilation shaft is 706m deep.
To address the challenges, the contractor, China Communications Construction Co, broke down the construction into smaller, more manageable segments, allowing for faster excavation. As a result, the original construction time was shortened by more than 25%.
To minimise the environmental impact on the Tianshan No. 1 Glacier and snow leopard habitats, on-site facilities were established to contain wastewater and fully use gravel.
