At 15:00 on August 28, with a crisp blasting roar, the last portion of rock and soil at the tunnel face was cleared, and the Xiahuangtian Tunnel—the longest tunnel on the entire Meizhou-Longchuan High-Speed Railway line, constructed by China Railway 25th Bureau Group—was holed through, marking the completion of all 52 tunnels along the line and laying a solid foundation for the scheduled opening and operation of the Meizhou-Longchuan High-Speed Railway.

The Meizhou-Longchuan High-Speed Railway has a main line length of approximately 93.98 kilometers. It is the first high-speed railway project in Guangdong Province to be fully funded and constructed by the province, and a major project promoting close ties between Meizhou, Heyuan and the Guangdong-Hong Kong-Macao Greater Bay Area. The line starts from Meizhou West Station of the Meizhou-Shantou High-Speed Railway, passes through Meixian District and Xingning City and Wuhua County of Meizhou City and Longchuan County of Heyuan City, and terminates at Longchuan West Station of the Ganzhou-Shenzhen High-Speed Railway.

As the longest tunnel and a controlling project on the entire line, the Xiahuangtian Tunnel is 7,377 meters long with a maximum burial depth of 290 meters. The tunnel passes through multiple geological fracture zones and strongly developed karst zones in the mountainous area, with abundant groundwater, complex geological conditions, great construction difficulty and high safety risks, making it the "throat" project of the entire high-speed railway construction.

Since the start of construction, the builders have adopted the methods of "long tunnel excavated in short sections" and inclined shaft excavation, carrying out multi-point construction and coordinated operations to ensure smooth progress. "By adding inclined shafts, we increased the main tunnel from two working faces to four, doubling construction efficiency. After the high-speed railway is opened for operation, the inclined shafts will continue to be used as emergency and rescue passages," introduced Shen Xianhua, chief engineer of the Meizhou-Longchuan High-Speed Railway Section 4 project of China Railway 25th Bureau Group.

It is understood that the application of intelligent technology and advanced techniques provided a strong guarantee for the smooth holing-through of the tunnel. The project builders innovatively applied new equipment and techniques such as tunnel personnel positioning safety helmets, harmful gas monitoring systems, real-time video surveillance, support void detection and 3D holographic scanning analysis, and processed tunnel slag into manufactured sand for reuse in site construction, achieving environmentally friendly disposal of waste slag and injecting scientific and technological innovation into tunnel construction in terms of personnel safety, engineering quality and green construction.

After the Meizhou-Longchuan High-Speed Railway is completed and opened to traffic, the travel time by high-speed rail from Meizhou to Guangzhou, Shenzhen and other Guangdong-Hong Kong-Macao Greater Bay Area cities will be shortened to 1.5 hours, which will greatly enhance the transport capacity of the corridor and improve transport organization. It is of great significance for accelerating the construction of a high-speed railway corridor linking the Pearl River Delta and eastern Guangdong with Meizhou and Heyuan, improving the layout of Guangdong Province's high-speed railway network, and promoting regional economic development.