On October 25, 2026, the last muffled sound came from the deep vein of Mount Taishan. With the smooth meeting of the two palm faces, the Anziling Tunnel, invested by Shandong Railway Investment Group, organized and constructed by Lunan High speed Railway Company, and constructed by China Railway Fifth Bureau, has achieved full tunnel connectivity. The builders who excavated from both the import and export directions, inch by inch in the mountainside, finally opened up this 3940 meter long single hole double track tunnel, laying a solid foundation for key construction processes such as beam erection and ballastless track.

The mountain crossing battle at the foot of Mount Taishan Mountain

The tunnel is located in Tai'an City, passing through complex strata in mountainous areas, with alternating distribution of Class II to V surrounding rocks. The rock mass is fragmented, like drilling a hole in a tofu block, and a slight mistake may cause instability and collapse. As a key control project for the entire Jizao Railway, it is also located in an ecologically sensitive area with high standards for environmental protection and water management. The pressure of construction organization and safety quality control is superimposed. In the face of complex geology and multiple challenges, the project team adheres to the construction concept of ensuring tooling, quality, and safety, and regards smooth blasting and secondary lining anti stripping as the core focus of tunnel quality control, solidly promoting standardization, refinement, and digital control.

Fine skills with one shot and one evaluation

After completing each excavation cycle, technicians use 3D laser scanning equipment to quickly scan the cross-section, which is equivalent to performing a high-precision CT scan on the newly excavated tunnel. They dynamically review the layout of boreholes and charge parameters, implementing a closed-loop management of one shot, one evaluation, and one adjustment. By relying on this method, the half hole mark rate of Class III surrounding rock remains stable at over 95%, achieving synchronous improvement in safety, quality, and efficiency. The cavity behind the lining is a common quality problem that troubles tunnel construction. The project first uses 3D laser scanning to detect the initial support contour, and then adopts a fully automatic material distribution system for layered pouring and top punching process, and implements mold grouting to prevent cavities from the source. The relevant process has been promoted throughout the Jizao Railway. At the same time, advanced geological forecasts are synchronized and followed up, and the geological conditions in front of the palm face are grasped in advance. Excavation methods and support parameters are adjusted in a timely manner; Implement the concept of combining permanent and temporary facilities at the entrance of the tunnel, coordinate the construction of tunnel protection and temporary facilities, and implement environmental protection facilities such as sprinkler dust reduction and sewage treatment in one step. The engineering construction and ecological protection should be carried out in parallel, and intelligent construction and green construction should be carried out simultaneously.

From a mountain to a line

The Anziling Tunnel is just a node on the entire line. Previously, nodes such as the Jinxiangshan No.2 Tunnel and 37 special structural bridges in the Zaozhuang section have successively achieved success. As of now, 12 out of the 18 tunnels along the Jizao Railway have been connected, and 48 continuous beams including the Guangming Avenue have been completed. The roadbed, bridge, and tunnel engineering have been completed by 62%, 79%, and 76% respectively, and the project construction is advancing at full speed.keywords:Engineering infrastructure

The Jizao Railway has a total length of 268.48 kilometers and a designed speed of 350 kilometers per hour. The entire line is equipped with 10 stations including Jinan East, Licheng, Nanshan, Tai'an East, Ningyang East, Qufu East, Zoucheng, Tengzhou East, Zaozhuang South, and Taierzhuang, connecting one mountain, one water, one sage, and Taierzhuang's red tourism resources. The project will start construction in December 2023 and is planned to be completed and opened to traffic in December 2027. After completion, it will be interconnected with the Rilan High speed Railway, Jiqing High speed Railway, Jiaoji Passenger Dedicated Line, and Jibin High speed Railway, opening up a fast track between the provincial capital economic circle and the Lunan economic circle. It will also end the history of no high-speed railway in the southern mountainous areas of Jinan and promote high-quality tourism and economic and social development along the line.Editor/Yang Meiling