On March 26, the "Qiangji" (Strong Foundation), the world's largest-diameter earth pressure balance (EPB)-dual shield combined TBM jointly developed by CRCC Heavy Industry and China Railway 18th Bureau Group, rolled off the production line in Changsha, Hunan. The equipment will be used in the construction of the 12.28-kilometer water conveyance tunnel on the southern section of the north-south line of the follow-up western channel project of the Hangjiahu South Drainage Project, marking a major breakthrough by China in the field of super-large-diameter tunnel boring equipment and injecting new technological momentum into urban flood control and drainage and underground space development.  

Roll-off ceremony site

Liu Yi, Party General Branch Secretary, Chairman and General Manager of Hangzhou Nanpai Water Conservancy Development Co., Ltd., delivers a speech

He Yongjun, Deputy Party Secretary and Deputy General Manager of CRCC Heavy Industry, delivers a speech

It is understood that the "Qiangji" has an excavation diameter of 12.68 meters, an overall length of 107 meters and a total weight of about 3,500 tons, making it the world's largest-diameter EPB-dual shield dual-mode boring machine at present. In response to complex strata conditions such as uneven hardness and alternating soft and hard ground in the tunnel, the "Qiangji" adopts a "TBM + shield" coexisting dual mucking system and a modular dual-mode cutterhead design, creatively solving the challenge of boring in complex strata and improving the overall construction quality and efficiency of the tunnel boring machine.

Workshop site

At the same time, the "Qiangji" deeply integrates digital technology and is equipped with an intelligent auxiliary boring system and an automatic segment lifting and transport system. Operators can monitor more than 20 parameters, including cutterhead rotation speed and advance rate, in real time through an intelligent interface, and rely on an automated guidance system to keep boring deviation at the millimeter level. The application of digital twin technology enables visual management and control of the entire construction process, driving the transformation of underground engineering toward "fewer personnel and greater intelligence."  

It is reported that the follow-up western channel project of the expanded Hangjiahu South Drainage Project is the deepest tunnel drainage system project in China in terms of drainage scale, tunnel diameter and burial depth. Its main task is flood control and drainage, while also improving the water ecological environment. Once completed, the project will further ease flood control pressure in the Taihu Lake basin, safeguard flood control and drainage safety in western Hangzhou, build a safety barrier for the main urban area of Hangzhou, and be of great significance in providing water security for promoting high-quality regional economic development.