In the heart of China’s energy infrastructure projects, a groundbreaking study is set to revolutionize shield tunneling in soft soils, offering significant implications for the energy sector. Led by ZHAO Kai from the College of Architecture and Engineering at Xinjiang University, this research tackles the persistent challenges of attitude control for shield machines traversing soft and weak strata, such as loess and coastal soft soil.
Shield tunneling is a critical method for constructing tunnels, particularly for energy pipelines and infrastructure projects. However, navigating soft soils has always been a formidable task, often leading to costly delays and potential structural failures. ZHAO Kai’s study, published in the Journal of Mining Science, introduces a novel method for calculating loosened soil pressure, drawing on the modified ellipsoid theory. This approach aims to enhance the precision of shield machine operations in cohesive soil layers, a common challenge in many energy sector projects.
The research establishes a theoretical model for shield-machine-soil interaction, utilizing equivalent soil springs to analyze vertical displacement, pitch angle changes, and attitude adjustments. This model was put to the test during the construction monitoring of the South Line of Hanjiang-to-Weihe River Water Diversion Phase Ⅱ Project, traversing the loess plateau. The results were striking. “The theoretical model demonstrated remarkable accuracy in predicting attitude changes and correcting thrust calculations,” ZHAO Kai explained. This validation underscores the potential of the model to significantly improve the efficiency and safety of shield tunneling in soft soil strata.
One of the key findings of the study is the sensitivity analysis of various parameters. The research reveals that the vertical displacement and vertical force of the shield machine exhibit a parabolic variation, while the pitch angle and vertical plane torque show a cubic parabolic variation. As the torque increases, the shield machine’s attitude transitions from a downward pitch to an upward pitch. This insight is crucial for engineers, as it provides a clearer understanding of how to adjust the propulsion system to control settlement and correct the pitch angle.
Moreover, the study highlights that as the proportion of soft soil in the strata increases, the settlement and downward pitch of the shield machine also increase. This information is invaluable for energy sector projects, where accurate predictions and adjustments can mean the difference between a successful operation and a costly setback. “Adjusting the propulsion system generates a low significant thrust difference in the upper and lower parts of the shield tail, which could realize settlement control of the shield machine and correction of pitch angle,” ZHAO Kai noted. This finding opens up new possibilities for more precise and efficient tunneling techniques.
The implications of this research are far-reaching. For the energy sector, where infrastructure projects often involve traversing challenging terrains, this study offers a robust solution to one of the most persistent problems in shield tunneling. By providing a more accurate method for calculating loosened soil pressure and a reliable theoretical model for shield-machine-soil interaction, ZHAO Kai’s work paves the way for more efficient and cost-effective tunneling operations.
As the energy sector continues to expand, the demand for reliable and efficient tunneling methods will only grow. This research, published in the Journal of Mining Science, translated from Chinese as ‘Journal of Mining Science’, sets a new standard for shield tunneling in soft soils, promising to shape the future of energy infrastructure projects. With its potential to reduce delays, minimize structural failures, and enhance overall project efficiency, this study is a game-changer for the industry. As engineers and researchers delve deeper into these findings, the future of shield tunneling looks brighter than ever, heralding a new era of precision and reliability in the energy sector.