The article discusses the construction of tunnels on Taiwan's High-Speed Rail Line, which is a large project. There are 42 tunnels of different lengths, and the article talks about how they were built. It mentions the excavation rates, casting production, and lining installation. The article also explains the tunnel geometry, construction methods, and the geology of the area. It mentions the support for the outer lining and the final inner linings. Some ground stabilization techniques were used due to drive instability.