On January 26, the world's first large-section horseshoe-shaped shield machine, independently designed and manufactured by China Railway Engineering Equipment Group, safely and successfully completed the 3,056-meter loess tunnel of the project, marking that China's overall technology for large-section horseshoe-shaped shield machines has reached a world-leading level.
This is also the first time that the "special-shaped shield method" has been used in the field of domestic railway mountain soft-soil tunnels, providing a vivid example for the construction of tunnels with similar geological conditions in the future, and has milestone significance in the history of China's railway tunnel construction technology and equipment development.
Yuan Liangshu, Deputy General Manager of Mengxi-Huazhong Railway Co., Ltd.; Han Yue, Commander of the Meng-Shaanxi Headquarters of Menghua Company; Yu Xingyi, Director of the Science and Technology Information Department of China Railway Group Co., Ltd.; Gao Guangyao, Deputy Secretary-General of the Yulin Municipal Government; Guo Ming, Deputy Director of the Yulin Railway Office; Zhang Hechuan, Party Secretary and Chairman of China Railway No.4 Engineering Group Co., Ltd.; Li Jianbin, Deputy Party Secretary and General Manager of China Railway Hi-Tech Industry Corporation Limited; and Bu Zhaohua, Deputy Party Secretary, Secretary of the Discipline Inspection Commission, and Chairman of the Labor Union of China Railway Equipment, and other leaders attended the breakthrough ceremony.
On July 17, 2016, the world's first horseshoe-shaped shield machine, jointly developed by China Railway Equipment and the construction contractor China Railway No.4 Engineering Group, with a total length of 118 meters, a weight of 1,300 tons, and a cutterhead 10.95 meters high and 11.9 meters wide, successfully rolled off the production line at the TBM Industrialization Center of China Railway Equipment. This globally pioneering tunnel excavation method can greatly improve the space utilization rate of the tunnel, reducing the excavation area by 10% to 15% compared with a circular cross-section, thereby reducing project costs and shortening the construction period. The equipment officially began excavation on October 29 of that year, and successively successfully passed through major risk source areas such as shallow cover layers, natural gas pipelines, and the Baotou-Maoming Expressway. In March 2017, it set a new construction record of 308.8 meters of excavation per month.

On April 1, 2017, the horseshoe-shaped shield machine's excavation exceeded 1,000 meters; on August 25, 2017, it exceeded 2,000 meters; on January 3, 2018, it surpassed the 3,000-meter mark; and now it has achieved full breakthrough. Baicheng Tunnel is located at the junction of the Mu Us Desert and the Loess Plateau in China, with soft soil and soft rock geology and soft soil quality. The mining method was used for construction, which had low efficiency and was prone to construction risks such as collapse and subsidence. The new excavation mode using the world's first "special-shaped shield method" not only effectively avoids the risk of collapse and subsidence, but also has extremely high construction efficiency, with a maximum excavation speed of 60 mm/min and a monthly excavation of 200-300 meters, effectively shortening the construction period. It has built a high-quality, efficient, safe, and environmentally friendly tunnel for the Menghua Railway, China's largest coal transport dedicated line, and also provided scientific data and valuable experience for the application of the "special-shaped shield method" in railway mountain soft-soil and soft-rock tunnels.

The use of the "shield method" in tunnel construction is not only safe, high-quality, and efficient, but also greatly improves the working environment, completely changing the traditional railway tunnel construction's high safety risks, harsh working environment, and low construction efficiency. On the horseshoe-shaped shield machine at the Baicheng project, a "shield cafe" appeared for the first time at the tunnel construction site. After intense and orderly shield excavation work, workers can drink a cup of coffee to refresh themselves and then continue to devote themselves to the busy work—what a happy thing.

China Railway Equipment has always adhered to the innovation-driven development strategy and continuously accelerated the independent and intelligent development of China's special-shaped shields. While achieving outstanding results in fields such as conventional shield machines, super-large cross-section shield machines, and rock tunnel boring machines, it has developed a series of innovative products such as horseshoe-shaped shield machines, rectangular shield machines, combined shield machines, and U-shaped shield machines, providing all-round equipment support, technical guarantees, and high-quality technical services for China's tunnel engineering and underground space development and construction.