On the morning of April 18, the tunnel on the section from the Museum Station to the Jiudu West Road Station of Luoyang Rail Transit Line 2, China's first tunnel to pass beneath the Luo River, was completed. The tunnel was built by the China Railway Tunnel Group, marking important progress in the construction of Line 2's "throat project."
The completed Bo–Jiu section tunnel of Luoyang Rail Transit Line 2 has a total length of 2,017 meters, including a 600-meter section beneath the Luo River. The Luo River holds an important place in the development of Chinese civilization. The central area where it meets the Yellow River is known as the "Heluo region," the birthplace of Chinese civilization, and Heluo culture is also called the root culture of the Chinese nation.
The Luo River is an important tributary of the Yellow River, with abundant water. The stratum beneath the riverbed is loose and consists of water-rich sand and gravel, with individual particles of high strength and large diameter. Shield tunneling involves many uncontrollable factors, making the project extremely difficult and rarely seen in China. Wang Fuming, Chen Xiangsheng, and other academicians of the Chinese Academy of Engineering called it a "world-class construction challenge."
During construction, the shield machine encountered large-diameter cobbles, which frequently clogged the equipment. Builders from the China Railway Tunnel Group measured and recorded the particle size of each discharged cobble and compiled statistics to accurately determine the cobble content. They also carefully studied the flow patterns and trajectories of cobbles in the slurry pipeline, and modified the stone-collection box more than 30 times. Tunneling speed increased from less than one ring per day at the start to a maximum of seven rings per day, greatly improving tunneling efficiency.
While the shield passed beneath the Luo River, it repeatedly encountered high water pressure and shallow cover, and the cutterhead was frequently jammed. The project team monitored tunneling parameters daily, conducted timely analysis and judgment, and adjusted parameters in real time to ensure the shield passed safely through the Luo River. At the same time, by strengthening specialized shield construction, enhancing scientific and technological research and technical briefings, and reinforcing team execution, they ensured that the entire construction process remained safe and controllable.
Luoyang, the capital of thirteen dynasties, has a civilization history of more than 5,000 years, a city-building history of more than 4,000 years, and a history as a capital of more than 1,500 years. Luoyang is the first non-provincial-capital city in central and western China to receive approval to build rail transit. The east-west Luoyang Rail Transit Line 1 began operation in March 2021, while Line 2 is a north-south trunk line that will greatly ease urban traffic pressure once completed and opened to traffic.