During the installation and construction of the signaling system for the northern section (Phase II) of Shanghai Metro Line 11, China Railway Fourth Bureau Electrification Company actively carried out QC group technological research and development, summarized a complete set of construction process methods, and successfully solved the problem of cable bracket installation in metro tunnels, providing a good reference for similar projects.
During the operation of urban subways, the long-term vibration from trains in tunnels can easily cause the fiber optic cable supports installed on the tunnel walls to loosen or even fall off, resulting in the cables falling into the tunnel and encroaching on the tunnel's boundaries. In severe cases, this can affect the normal operation of the subway. The northern section (Phase II) of Shanghai Metro Line 11 is 23.2 kilometers long, of which 21.046 kilometers are in tunnels. More than 42,100 sets of cable supports need to be installed. Ensuring that the supports are installed successfully on the first attempt is the biggest challenge encountered in the construction process.
The project team established a dedicated QC task force. Through on-site trial installation and statistical analysis, it was found that unclean drilling and insufficient hole depth affected the support construction quality in 97% of cases. The main problems affecting the installation pass rate were insufficient worker skills, accidental material damage during construction, and insufficient air pressure from the air blower to remove dust from the borehole. To address these issues, the project team invited experienced technicians to provide on-the-job training to the workers, who were certified to work after passing practical assessments. Traditional air blowers were technically modified by extending the nozzle to thoroughly remove dust from the borehole. During on-site construction, construction procedures were rationally arranged, and the protection of materials, equipment, and finished products was strengthened to ensure safe and high-quality progress of construction.
Through the implementation of a series of optimization measures, the installation of over 40,000 cable supports along the entire line was standardized, secure, and uniform, with the first-time installation qualification rate rapidly increasing from 86.5% to 99%. Statistics show that this QC technology breakthrough improved construction quality while reducing project costs by approximately 310,000 yuan, achieving significant economic benefits. The achievements have successively won honors such as the First Prize for Excellent QC Achievements from China Railway Fourth Bureau, the Excellent Quality Management Group Award from China Railway, the First Prize for Excellent QC Group in Shanghai Engineering Construction, and the National Excellent Quality Management Group Award.
