On the evening of June 13, the first secondary lining of the Hongshi Tunnel in Section 05 of the Puyan Expressway, constructed by the Mechanization Company of China Railway No.5 Engineering Group, was successfully poured, marking the smooth launch of full-process construction of the tunnel.

The Hongshi Tunnel is located in Yalugou Village, Hongshi Town, Huadian City, Jilin Province. With a total length of 3,130 meters, it is one of the key control projects among the "three tunnels and four bridges" along the entire Puyan Expressway and the only extra-long tunnel on the whole line. Section 05 is responsible for the 1,525-meter construction task at the exit end of the Hongshi Tunnel. Both the left and right exit portals of the tunnel adopt the cut-bamboo type. The maximum buried depth of the tunnel is 191.3 meters. The overall geological conditions of the tunnel are poor, with Grade IV and Grade V surrounding rock accounting for 89.5%, posing high safety risks and great construction difficulties.

To ensure the smooth pouring of the first secondary lining, the project department formulated a special construction plan and carried out scientific monitoring and measurement. It exercised refined control over trolley design and processing, concrete mix proportion design, and pouring techniques, and implemented safety and quality control from the source, laying the foundation for the smooth launch of full-process construction of the tunnel. According to the plan, the left and right lines of the Hongshi Tunnel will be holed through in March 2023.