Abstract
With the development of modern economy and the progress of the era, cities continue to develop and prosper. In the process of urban construction, shield tunneling is gradually being adopted in the construction of power tunnel projects. To address the inherent limitation of insufficient launching shaft length for power tunnels, the split launching technology modularly dismantles the shield machine and launches it in sections, breaking through the rigid requirement of traditional integrated construction for shaft depth ≥100m, and enabling safe launching within confined spaces (shaft length ≤100m). This achieves "space intensification, schedule controllability, and cost optimization," shortening the construction period and reducing costs compared to traditional cut-and-cover methods. This paper is based on a power tunnel project in Guangzhou, where the structural dimensions of the launching shaft are 64.6m in length, 11.35m in width, and 14.8m in depth. Through the split launching technology, the project successfully overcame the challenge of limited construction site for power tunnels, achieving a balance between excavation efficiency and safety. Through the combination of glass fiber reinforced concrete (GFRP) retaining piles and direct shield cutting technology, reducing the risks of manual intervention, as well as optimizing modular trolley assembly and dynamic transportation systems to adapt to narrow underground spaces; engineering practice demonstrates that this technology can significantly enhance the economy and adaptability of urban underground engineering, providing important technical reference for similar projects, and greatly improving the construction efficiency and economic benefits of power tunnel engineering.
Full Text
Preamble
A Brief Discussion on the Split Launch Technology of Earth Pressure Balance Shield in Power Tunnels
Li Henan
Guangzhou Metro Engineering Consulting Co., Ltd., Guangzhou 510000, China
Abstract: With modern economic development and social progress, cities continue to grow and prosper. In urban construction, shield tunneling is increasingly being adopted for power tunnel projects. To address the inherent limitation of insufficient launch shaft length, split launch technology breaks down the shield machine into modules and launches it in sections, overcoming the traditional rigid requirement of shaft depth ≥100 m for complete machine construction and enabling safe launch in confined spaces (shaft length ≤100 m). This achieves spatial efficiency, schedule controllability, and cost optimization, shortening the construction period and reducing costs compared to traditional cut-and-cover methods. Drawing on a power tunnel project in Guangzhou, where the launch shaft dimensions are 64.6 m long, 11.35 m wide, and 14.8 m deep, this paper demonstrates how split launch technology successfully overcame site constraints, achieving a balance between excavation efficiency and safety. Through the combination of glass fiber reinforced concrete retaining piles and direct shield cutting technology, risks associated with manual intervention were reduced, while modularized trolley assembly and optimized dynamic transportation systems adapted to the narrow underground space. Engineering practice demonstrates that this technology can significantly improve the economy and adaptability of urban underground projects, providing important technical reference for similar projects and greatly enhancing the construction efficiency and economic benefits of power tunnel projects.
Keywords: power tunnel; split; shield; space