https://www.youtube.com/watch?v=28G9AMhHFoQ

China's rapid development in the field of tunnel boring machines (TBMs) has surprised the world. Just over twenty years ago, China faced foreign restrictions in this area, but today it has become a global leader. Chinese TBMs outperformed foreign counterparts in terms of speed during the construction of the Chengdu Metro, marking China's ownership of this technology. The victory signaled the failure of foreign efforts to block China's progress in TBM manufacturing. Despite initial challenges, China prioritized TBM research and manufacturing, eventually achieving breakthroughs. Initially relying on imports, China gradually gained knowledge and expertise through collaborations with the United States and independent research. In 17 years, China successfully developed its first shield tunneling machine, the "Tieyi No. 1," demonstrating remarkable progress in infrastructure construction.