In the bustling world of underground construction, the dance between new and existing infrastructure is a delicate one. As cities expand and infrastructure ages, the need to build new tunnels without disrupting existing ones becomes increasingly critical. A recent study led by HUANG Jianhua from the Department of Civil Engineering at Fujian University of Technology, Fuzhou, China, sheds light on the intricate interactions between pipe jacking and existing metro shield tunnels, offering valuable insights for the construction industry and the energy sector.
The study, published in ‘Chengshi guidao jiaotong yanjiu’ (Urban Rail Transit Research), delves into the complex dynamics of underground excavation projects, particularly focusing on the impact of pipe jacking on existing metro shield tunnels. Pipe jacking, a trenchless method used for installing pipes, cables, or other utilities, is increasingly popular due to its minimal surface disruption. However, its interaction with existing tunnels can be a double-edged sword, potentially causing significant deformation if not managed properly.
HUANG Jianhua and his team conducted a simulation analysis based on an actual engineering case, examining the impact patterns of pipe jacking both vertically crossing and parallel to an existing metro shield tunnel. The results were then validated against real-world measurement data, providing a robust foundation for their findings.
The study revealed that the deformation of the existing tunnel decreases as the distance from the pipe jacking increases. During vertical crossing, the maximum deformation occurs at the central axis of the pipe jacking. “Within 12 meters of the pipe jacking excavation face from the central axis of the metro shield tunnel, the deformation of the metro shield tunnel reaches its maximum,” HUANG Jianhua noted. This finding underscores the importance of careful planning and monitoring during such operations.
For parallel construction, the influence zone primarily extends 20 meters ahead of and 10 meters behind the pipe jacking excavation face. This information is crucial for engineers and planners, as it helps define the safe zones and potential risk areas during construction.
The implications of this research are far-reaching, particularly for the energy sector. As cities continue to grow and the demand for energy increases, the need for efficient and safe underground infrastructure becomes paramount. Understanding the impact of pipe jacking on existing tunnels can help energy companies plan and execute their projects more effectively, minimizing disruptions and ensuring the safety of their infrastructure.
This research is a significant step forward in the field of underground construction. By providing a clearer understanding of the interactions between pipe jacking and existing tunnels, it paves the way for more precise and efficient construction methods. As HUANG Jianhua’s work shows, the future of underground construction lies in the careful balance of innovation and precision, ensuring that our cities can continue to grow and evolve without compromising their existing infrastructure.