Recently, the multi-specification tunnel boring machine main bearings independently developed by CRCHI have passed condition-simulation test verification and entered the stage of batch engineering application.

Key technologies urgently need innovation

The tunnel boring machine is high-end equipment in the field of tunnel engineering construction, undertaking the important task of rock drilling and road opening and building major national infrastructure projects across rivers and seas. As its core key component, the main bearing works for a long time in underground tunnels, and its reliability and safety requirements are extremely high. Once a failure occurs, it is difficult to disassemble and replace, which will paralyze construction and cause huge losses. Previously, due to the lack of test and application data support, domestic main bearings were difficult to effectively verify product reliability, and engineering application advanced with great difficulty.

Dedicated research breaks through constraints

To break through the three major dilemmas faced by domestic main bearings—"unusable, dare not use, unwilling to use"—CRCHI carried forward the railway corps spirit of "cutting roads through mountains and building bridges across waters," leveraged its advantages of understanding both tunnel boring machine design and main bearing operating conditions, combined construction application experience, collected load data under complex operating conditions, and carried out targeted research and development matching the characteristics of the operating conditions. It broke through key core technologies across the entire life cycle, including high-performance materials, highly reliable design, high-precision manufacturing, and highly credible testing for main bearings, replicated condition-simulation tests of main bearings under soft soil, hard rock, and uneven soft-hard geology, and systematically verified the long-life service capability of independently developed main bearings to adapt to complex and harsh operating conditions, laying a solid foundation for the batch engineering application and industrialization development of domestic main bearings.

Let facts speak, move forward bravely

In promoting the engineering application of domestic main bearings, CRCHI overcame numerous obstacles, let technical strength and test data speak, and steadily advanced the application of domestic main bearings in stages and batches. It has accumulated more than 20 kilometers of tunneling in typical representative projects, with application sites ranging from coastal cities to the central and western regions, including nearly ten provinces and cities such as Beijing, Shanghai, Shenzhen, Changsha, Xuzhou, and Inner Mongolia; application scenarios covering multiple key projects such as shaft exploration, oil pipelines, urban subways, and pumped storage; and application geology covering unstable soft rock strata, composite strata with uneven soft-hard conditions and high-pressure fluctuations, and full-face hard rock strata. In particular, in the Pearl River Delta region, long known as a "geological museum," it overcame multiple tests of harsh geological conditions such as 130 MPa extremely hard granite, multiple sections of large-depth upper-soft lower-hard strata, and high-pressure frequently changing strata in long and large tunnels, and successfully achieved breakthrough of the target tunnel project section, fully verifying the reliability and stability of domestic main bearings.

The serialized independent development and large-scale engineering application of domestic main bearings have broken the long-standing domestic stereotype of turning pale at the mention of "domestic main bearings," provided firm confidence for solving the "bottleneck" problem of core components of tunnel boring machines, and provided a strong guarantee for promoting the safe and high-quality development of the tunnel boring machine industry.