The world's largest earth pressure balance (EPB) double shield hybrid tunnel boring machine (TBM), named "Qiangji", officially rolled off the production line on March 26 in Changsha, Hunan Province.

Developed by CRCC, the "Qiangji" TBM has a maximum boring diameter of 12.68 meters, is 107 meters long, and weighs 3,500 metric tons. This ultra-large machine will be used for a 12.28-kilometer water tunnel in the southwestern drainage project of Hangzhou.

This project represents China's most ambitious deep tunnel drainage system to date, setting national records for urban drainage scale, tunnel diameter, and depth. It marks the country's first attempt at implementing a super-large urban deep tunnel drainage project. While primarily designed for flood control and drainage, the project will also contribute to improving the region's aquatic ecosystem.

In response to complex geological conditions, such as uneven soil layers and alternating soft and hard strata, the "Qiangji" TBM features a dual-mode design that combines earth pressure shield and double shield TBM technologies. This innovative design creatively solves the challenges posed by mixed terrain and significantly boosts construction efficiency. The machine is also equipped with advanced intelligent tunneling systems and predictive geological technology, further enhancing its automation and precision.

The project will alleviate flood risks in the Taihu Lake Basin, enhance flood resilience for western Hangzhou and establish an urban safety barrier for the city's main districts.