Recently, the Fuzhunmiao Village Station–Zhucun Station section of the first phase of Xi'an Metro Line 15 achieved dual-line breakthrough. This marks the first time in Xi'an metro construction that the "shield tunneling first + later expansion excavation" method has been used to cross a ground fissure section.

It is understood that this method is an innovative approach in which, when a metro tunnel crosses a ground fissure section, the shield machine passes through first, followed by ground reinforcement and expansion excavation. Compared with the traditional "mined excavation + shield empty pushing" method, it eliminates a series of complicated construction steps such as vertical shaft and cross-passage excavation, manual work using the CRD method, and in-tunnel shield reception and launching. Through structural and method optimization, it enables convenient and efficient crossing of ground fissure sections by metro tunnels, shortening the construction period and optimizing the work sequence while also reducing the impact of construction operations on surface traffic and the environment.

The section from Fuzhunmiao Village Station to Zhucun Station is about 1,318.4 meters long, and the expansion excavation section is about 215 meters long. During construction, Xi'an Rail Transit Group, together with China Railway Construction, established a scientific research task force to carry out research on how to safely, quickly and efficiently remove the segment lining in the ground fissure expansion excavation section. Industry experts were invited to discuss and verify the approach, and the construction plan was continuously optimized. After more than 10 trials, a mobile hydraulic mechanical device for rapidly removing shield tunnel segments inside a completed shield tunnel was successfully developed, solving the problems of low mechanization, high safety risk and long construction cycles in conventional shield tunnel segment removal. The removal of 287 rings of segments in the expansion excavation section was completed safely, efficiently and quickly. At the same time, through continuous optimization in aspects such as construction technology, equipment configuration and personnel organization, and on the premise of ensuring controllable safety and quality, the expansion excavation efficiency was increased from 4–5 days per ring to 1.5 days per ring, shortening the construction period while providing an effective reference for subsequent construction.

In addition, the left line of the shield tunnel section from Youdian College Station to Yinghua Square Station of the first phase of Line 15 also achieved breakthrough recently. The first phase of Xi'an Metro Line 15 runs from Xiliu Station in the west to Hanjiawan Station in the east, connecting three major areas of the southern main urban area: the High-tech Zone, Chang'an District and the Aerospace Industry Base, and driving population and economic development along the line. Once completed, it will further improve the rail transit network structure in the southern part of the city.

Up to now, 9 of the 13 stations on the first phase of Xi'an Metro Line 15 have achieved capping of the main structure, and the tunnel sections have been completed 73.4% in total. The project is proceeding in an orderly manner.