In the realm of underground construction, stability is paramount, especially when it comes to deep-buried shield tunnels. These tunnels, often used for water diversion or other critical infrastructure, face unique challenges due to their depth and the pressures they endure. Recent research led by Xin Huang of Henan Polytechnic University sheds new light on the stability of excavation faces in these tunnels, offering insights that could revolutionize the way we approach deep-buried construction projects.
The study, published in the Electronic Journal of Structural Engineering, focuses on the Bailuyuan shield tunnel, part of the ambitious “Water Diversion from the Han to the Wei River” project. Huang and his team conducted a series of indoor tests and three-dimensional discrete element simulations to understand the stability and settlement characteristics of the tunnel excavation face under various conditions.
One of the key findings is the non-linear relationship between tunnel burial depth and the horizontal displacement of the excavation face. As Huang explains, “The horizontal displacement of the tunnel excavation face and the critical chamber earth pressure ratio increase nonlinearly with the increase of tunnel burial depth.” This insight is crucial for engineers designing and constructing deep-buried tunnels, as it highlights the need for more precise calculations and potentially new engineering approaches to maintain stability at greater depths.
The research also explored the impact of different excavation parameters, such as the cutterhead opening rate, excavation speed, and cutterhead rotation rate. The findings reveal that increasing the cutterhead opening rate leads to higher horizontal displacement, geological settlement, and critical chamber earth pressure ratio. Similarly, higher excavation speeds and cutterhead rotation rates exacerbate horizontal displacement and settlement, with the critical chamber earth pressure being more influenced by the rotation rate than the speed.
These discoveries have significant implications for the energy sector, where deep-buried tunnels are often used for transporting water, oil, or gas. The ability to predict and mitigate the risks associated with excavation face stability can lead to more efficient and safer construction processes, ultimately reducing costs and enhancing project timelines. As Huang notes, “The influence of the cutterhead opening rate and cutterhead rotation rate on the horizontal displacement of the excavation face is greater than on the settlement of the strata, while the influence of excavation speed on the settlement of the strata is greater than that of the horizontal displacement of the excavation face.” This nuanced understanding allows engineers to make informed decisions about excavation parameters, optimizing both safety and efficiency.
The research not only provides valuable data but also introduces a method for simulating and analyzing the stability of deep-buried shield tunnels. By calibrating microparameters of the strata and constructing a three-dimensional discrete element model, Huang’s team has paved the way for more advanced and accurate simulations in the future. This method could be applied to a wide range of construction projects, from water diversion to energy infrastructure, offering a new standard for ensuring stability and safety in deep-buried tunnels.
As the demand for underground infrastructure continues to grow, driven by urbanization and the need for sustainable energy solutions, the insights from this research will be invaluable. By understanding the complex interplay of factors affecting excavation face stability, engineers can design and build more robust and reliable tunnels, ensuring the longevity and safety of our critical infrastructure. The findings published in the Electronic Journal of Structural Engineering, also known as the “Journal of Structural Engineering” in English, represent a significant step forward in the field, offering a roadmap for future developments and innovations.
