Qingdao Metro Line 9 Jinghui Section Left Tunnel 1692.14 Meters Breaks Through

en.Wedoany.com Reported - On July 10, the left tunnel of the Jingcheng Road Station to Huicheng Road Station (Jinghui) section of Qingdao Metro Line 9 in Shandong, China, achieved a breakthrough. The tunnel has a total length of 1,692.14 meters, requiring the assembly of 1,128 segments, with a maximum burial depth of 25.4 meters. This breakthrough creates conditions for subsequent processes such as track laying and mechanical and electrical installation, and also accelerates the full-line opening process of Qingdao Metro Line 9.

The geological conditions along the Jinghui section are complex, with interbedded soft and hard rock layers. During construction, issues such as shield machine attitude deviation and cutterhead jamming are prone to occur, which may cause tunnel deformation and segment damage. The entire route includes nine geological fracture zones, accounting for nearly one-third of the total length. The area features developed fissures and abundant groundwater, with poor self-stability of the stratum, posing risks of water and sand inrush and ground settlement. High-strength hard rock is distributed within the section, with a maximum rock strength of 94.7 megapascals, exacerbating shield cutter wear and the difficulty of cutter replacement under pressure.

The project team established a management mechanism of "daily scheduling and daily review," adhered to the principle of "small adjustments with frequent corrections," dynamically optimized tunneling parameters, and precisely controlled the shield tunneling attitude. To address the challenges of construction in water-rich fracture zones, the team adopted a combined process of "advanced geological prediction + muck conditioning + round-the-clock intelligent monitoring" to pre-assess geological risks in advance. For tunneling through high-hardness rock layers, the team selected stable strata as working points, equipped safety protection and emergency support equipment, strictly implemented standardized operating procedures, and regularly performed cutter inspection and replacement.

The tunnel required a close undercrossing of the Qingxin Expressway viaduct, with a minimum pile spacing of only 5.22 meters, and the precision of subgrade settlement control needed to be within plus or minus 10 millimeters. The project activated a 24-hour automated intelligent monitoring system to track construction deformation data around the clock, employing the method of "low-speed steady advance, sufficient grouting, and fine control" to reduce disturbance to the surrounding stratum and ensure the safety and controllability of the undercrossing construction.

The project party strictly implemented the "Double Twenty Articles" essential safety management requirements of Qingdao Metro, formulated special construction plans and emergency response plans, regularly conducted realistic emergency drills for water and sand inrush and equipment failures, and stocked sufficient emergency materials while establishing a professional rescue team.

The project party built a BIM+shield intelligent integrated management and control platform, deploying full-area high-definition monitoring and intelligent sensing equipment to achieve millisecond-level collection and real-time transmission of core data such as tunneling speed, cutterhead torque, and grouting parameters. Through the digital system, construction plans were dynamically optimized, achieving a first-time acceptance pass rate of 90.5% for segment assembly. The project team will next optimize the construction plan to promote the double-line breakthrough of the Jinghui section.