In the heart of China’s rapid urbanization, a groundbreaking study is shedding new light on the intricate dance between underground tunnels and the bridges that span above. Led by Lan Deng of Hubei 9D Mapping and Design Co., Ltd., this research delves into the complex interactions between twin shield tunnel construction and the deformation of bridge pile groups, offering crucial insights for the energy sector and urban planners alike.
As cities expand and transportation networks grow, the demand for efficient and safe underground tunnels has surged. However, the excavation of these tunnels can significantly impact the surrounding soil and the foundations of elevated bridges, posing potential safety risks. Deng’s study, published in the journal Frontiers in Built Environment, which translates to “Frontiers in the Built Environment,” focuses on the Zhengzhou Metro Line 5, which crosses beneath the Shijiazhuang-Wuhan High-Speed Railway Bridge. This case study provides a real-world laboratory for understanding the mechanical responses of bridge pile groups to tunnel excavation.
Using a combination of three-dimensional finite element numerical simulations and field monitoring data, Deng and his team have uncovered some striking findings. “The excavation process affects the bridge piles at all stages,” Deng explains, highlighting the dynamic nature of the interaction between tunnels and bridge foundations. For single-track excavation, the maximum horizontal displacement of the pile group reaches 1.587 mm, while for double-track excavation, it increases to 1.813 mm. The settlement of the piles can reach up to 5.03 mm, underscoring the significant impact of tunnel construction on bridge stability.
One of the most compelling aspects of the study is the relationship between pile spacing and deformation. The research reveals that the maximum settlement and horizontal deformation of the bridge piles show a negative correlation with the minimum spacing between piles. As the spacing decreases, the deformation increases exponentially, a finding that has profound implications for the design and construction of urban infrastructure.
The study also highlights the varying impacts on different piles. Piles in close proximity to the tunnel, such as piles 17#, 18#, and 35#, experience more significant settlement and inclination, with maximum values reaching 4.5 mm and 0.008, respectively. In contrast, more distant piles, like 16#, 20#, and 34#, are less affected. This differential impact is crucial for engineers and planners, as it informs the design and reinforcement strategies for bridge foundations in areas prone to tunnel construction.
For the energy sector, these findings are particularly relevant. The construction of underground tunnels for energy infrastructure, such as pipelines and power cables, can have similar impacts on nearby structures. Understanding these interactions is essential for ensuring the safety and stability of both the tunnels and the structures above. “This research provides a foundation for more informed decision-making in the design and construction of urban infrastructure projects,” Deng notes, emphasizing the practical applications of the study.
As cities continue to grow and evolve, the need for sustainable and safe urban development becomes increasingly pressing. Deng’s research offers a roadmap for navigating the complexities of tunnel construction and its impact on bridge foundations. By providing a deeper understanding of these interactions, the study contributes to the sustainable development of cities, ensuring the safety and stability of the built environment within rapidly evolving urban social spaces.
The insights gained from this study are poised to shape future developments in the field, guiding engineers and planners in their efforts to build safer, more resilient cities. As urbanization continues to accelerate, the lessons learned from Deng’s research will be invaluable, helping to mitigate risks and ensure the longevity of urban infrastructure.