On May 20, the 8-meter-class main bearing for an ultra-large-diameter shield tunneling machine developed by CRCHI (China Railway Construction Heavy Industry Corporation) passed the installation application demonstration in Changsha. The review expert panel was headed by Qian Qihu, professor of the Army Engineering University of PLA, as group leader, and Chen Xiangsheng, professor of Shenzhen University, as deputy group leader, and consisted of nine experts from industry associations, universities, and user units, namely Su Zimeng, Jiang Yusheng, Zhu Weibin, Wu Zongyan, Sha Mingyuan, Xiao Mingqing, and Chen Jian. The panel listened to CRCHI's report on the development of the domestic 8-meter-class large-diameter main bearing, reviewed the relevant technical materials, and inspected the main bearing production line and the actual products on site. Huang Changfu, member of the Standing Committee of the CPC Committee and Vice President of China Railway Construction Corporation (CRCC), delivered the concluding speech; Lei Shengxiang, expert of CRCC, attended the meeting; Zhao Hui, Party Secretary and Chairman of CRCHI, delivered a speech; and He Yongjun, Deputy Party Secretary and Vice General Manager, chaired the meeting.

Demonstration meeting site

The review expert panel unanimously agreed that the CRCHI 8-meter-class main bearing, through independent research and design, independent processing and manufacturing, and reliability test verification on a test bench, meets the design requirements, with technical indicators reaching the international advanced level and some leading the world, and can be installed and applied in actual engineering.

The main bearing is the "heart" component of a shield tunneling machine and a core fundamental component addressing major national needs. It has been listed among the 35 "bottleneck" key technologies constraining China's industrial development. The localization of main bearings has received support from national strategies such as the Industrial Strong Foundation Project, the National Key R&D Program, and the Industrial Foundation Innovation Development Catalog, and its technical level, manufacturing precision, and quality requirements stand at the high point of the global industrial chain and value chain.

Main bearing series products

To resolve the long-standing contradiction of the core fundamental components of the shield tunneling machine industrial chain relying on imports and being constrained by imported brands, since 2019 CRCHI, with the support of key projects of national ministries and commissions and Hunan Province, has successively made breakthroughs in key technologies such as main bearing materials, design, manufacturing, and testing, built the largest main bearing production base in China, achieved independent development of main bearings of multiple specifications with a diameter of 8.61 meters and below, and completed the demonstration application of small and medium-diameter main bearings, effectively solving the "bottleneck" problem, ensuring the independence and controllability of the industrial chain and supply chain, and achieving remarkable social and safety benefits.

Experts inspected the main bearing production line and the actual products on site

The review expert panel held that the development and application of domestic main bearings has broken through the "last link" of the shield tunneling machine "bottleneck" technology, providing a solid guarantee for promoting the independence and controllability of the industrial chain in the underground engineering field; the major breakthrough in the localized application of 8-meter-class main bearings for ultra-large-diameter shield tunneling machines will greatly enhance the international competitiveness of China's high-end underground engineering equipment industry.

CRCHI leadership members Hu Bin, Liu Shaobao, Luo Jianli, and Han Jialin, as well as heads of relevant departments and units, attended the meeting.