At about 9:00 a.m. on the 1st, the "Peace" shield machine of the South Extension Project of Heping Avenue in Wuhan, Hubei Province broke through the ground at Huanghelou South Road, Wuchang District, marking the smooth completion of the largest diameter single-tube double-layer shield tunnel in China, laying a solid foundation for the opening of traffic at the end of the year. The total length of the project is 3042 meters, of which 1390 meters are constructed by a slurry balance shield machine with an excavation diameter of 16.03 meters. The shield segment has an outer diameter of 15.4 meters and an inner diameter of 14.2 meters. It has a single-pipe, double-layer, two-way and six-lane design speed of 50 kilometers per hour. According to Zhang Jianyong, the project leader of China Railway 14th Bureau, the shield machine started from the site area of "Wushengmen" on Zhongshan Road on August 29, 2021, and received at Huanghelou South Road. The maximum buried depth of the tunnel is 55 meters. The tunnel passes through Wuchang Ancient City, Beijing-Guangzhou Railway and other places. There are more than 500 old buildings and many former residences of celebrities on the line. In the process of tunnel excavation, there are many major risk sources, which is one of the tunnels with high technical content and difficulty in domestic construction. To this end, the big shield of China Railway 14th Bureau formed a shield technical expert group to guide the selection, design and construction of shield machines; For karst detection and treatment and long-distance hard rock excavation, the shield machine is equipped with a drill-injection integrated advanced geological drilling rig and advanced geophysical prospecting system, which is the first time in China to be applied on a 16-meter shield machine. In the process of tunneling, the automatic monitoring construction technology is applied to set up observation points for sensitive buildings and structures along the line, monitor the settlement data in real time, and adjust the tunneling parameters synchronously to achieve safe and stable crossing. In practice, we have explored and summarized innovative technological achievements and obtained many invention patents, including the settlement control technology for the construction of super-large diameter slurry shield passing through complex geological environment, and the research on the deformation law of super-large diameter shield passing through the metro tunnel in close proximity, which have been successively published in national professional journals. (Outlook New Era)