Recently, the section from Fenghuang Road Station to Wangsheren Station on Jinan Metro Line 6 successfully passed beneath the Jiaoji Railway and the Jiaoji Passenger Dedicated Line, with settlement of the operating railways controlled within 1 millimeter, demonstrating the construction team's expertise in complex conditions.

　　The shield tunneling for the section from Fenghuang Road Station to Wangsheren Station on Jinan Metro Line 6 is adjacent to the Jinan East Transportation Hub, located directly beneath and crossing at a right angle with Fenghuang North Road, the Jiaoji Railway, and the Jiaoji Passenger Dedicated Line. The shield tunneling sequentially passes beneath the Jiaoji Railway and the Jiaoji Passenger Dedicated Line, with only 80 meters between the two railway lines. Directly above the shield tunnel section are the busy Fenghuang North Road and the Jiaoji Railway bridge culvert, and the distance to the foundation of the Liuzhiyuan Middle Bridge of the Jiaoji Railway is only 11.76 meters.

　　Above the tunnel is soft silty clay, and below is harder diorite. A slight mistake could affect the operation of the existing lines, making construction very difficult. The double pressure of continuously passing beneath two existing railway lines brings a dual test of safety risks and construction difficulties to the shield tunneling team of Line 6.

　　To successfully complete the underpass task, the participating units continuously strengthened their sense of responsibility and safety awareness, adopted the "three tight focuses" construction strategy, and took key risk precautions to further control ground settlement, mitigate construction risks, and ensure construction safety, achieving zero safety accidents and zero risk warnings.

　　Safety management personnel reviewed the risks existing throughout the construction process, established a dual prevention mechanism of safety risk classification control and hidden danger investigation and governance, and proactively prevented safety risks. They focused tightly on preparatory work, arranged for equipment to enter the site in advance, stockpiled sufficient materials such as segment linings, and organized multiple scheme seminars to develop a practical and feasible construction plan based on actual geological conditions.

　　During construction, they focused tightly on on-site progress. Owner representatives and safety management personnel took turns on duty patrols, closely monitoring each construction procedure; operators and technical personnel maintained real-time linkage between the surface and underground, closely monitoring ground settlement changes, and adjusting various shield machine tunneling parameters in real time.

　　After construction, they focused tightly on finishing and aftermath, properly cleaning up the construction site and ensuring civilized construction; conducting summaries and experience exchanges on the underpass construction to improve capabilities for subsequent work.

　　100 meters before passing beneath the Jiaoji Railway and the Jiaoji Passenger Dedicated Line, the Line 6 construction team conducted high-standard trial tunneling, held multiple expert consultation meetings, continuously optimized construction parameters, adjusted the shield machine's advancing posture, and summarized shield tunneling experience to provide technical reference for subsequent underpass tunneling.

　　"Clay shock" is a special material that can effectively control ground settlement. During tunneling, construction personnel injected "clay shock" outside the shield body for each ring, allowing it to flow into all gaps of the shield machine shell, effectively wrapping the shield body, reducing disturbance to the strata, and preventing heave or subsidence.

　　The construction team also sampled and washed the muck from each ring, compared it with existing stratum survey results, confirmed the current tunneling status, and changed tunneling parameters at any time according to changes in the proportion of rock in the strata.

　　Through innovative measures, they maintained stable shield tunneling throughout the underpass construction of the existing railway, successfully reducing ground settlement and minimizing the impact on the normal operation of the existing lines.

　　With the joint efforts of all participating units, the two lines in the Feng-Wang section completed the underpass in only 31 days, ensuring quality while shortening the construction period, and reducing settlement while ensuring safety. After the underpass, the track settlement of the Jiaoji Railway and the Jiaoji Passenger Dedicated Line was only 0.7 millimeters, far less than the minimum warning value of 1.8 millimeters required by the control value.

　　Previously, this section also successfully passed beneath the operating Metro Line 3 and the Gongye North Road Viaduct with settlement values of 1.2 millimeters and 1.5 millimeters, respectively. The overall construction level and settlement values of the four underpasses rank among the top in Jinan's shield tunneling, achieving a "four consecutive victories" in safe and efficient underpass of existing lines.