Newswise — With the rapid development of urban infrastructure, the construction of complex interchange tunnel projects has become increasingly common. However, the deformation mechanism of the intersecting sections of interchange tunnels under excavation and overloading conditions remains a key challenge, and the effectiveness of support methods for such sections still needs in-depth verification.
Therefore, China University of Mining and Technology (Beijing), Guangzhou Daguang Expressway Co., Ltd., and Shenzhen Transportation Design & Research Institute Co., Ltd. have jointly carried out a research entitled “Investigation of Deformation Mechanisms in Intersecting Sections of Interchange Tunnels Using the Negative Poisson’s Ratio Anchor Excavation Compensation Method”.
This study focuses on the intersecting section of the Nalong Underground Interchange Tunnel in Shenzhen. It adopts physical model tests and numerical simulation methods to explore the deformation mechanism of the intersecting section under excavation and overloading conditions. First, based on the actual geometric characteristics, spatial distribution, and engineering geological conditions of the tunnel, the optimal similarity ratio is determined, and a physical model of the intersecting section is established. Then, following the excavation compensation theory, the intersecting section is excavated and supported using scaled Negative Poisson’s Ratio (NPR) anchor cables, and the stress redistribution characteristics of the tunnel during excavation are analyzed through tunnel stress-strain, displacement, and NPR anchor cable axial force. Subsequently, overloading tests are conducted on the tunnel to reveal the surrounding rock failure mechanism of the intersecting section. Finally, numerical simulations are used to compare and verify the test results. The research results show that the NPR anchor cables have excellent high-stress compensation characteristics, which can effectively resist the settlement of the support area and play a good supporting role in the intersecting tunnels. Meanwhile, the deformation of the intersecting section of the interchange tunnel under “excavation-overloading” conditions shows a two-stage law, and the “saddle-shaped” displacement field formed at the intersection of the two tunnels is consistent with the numerical simulation results. This study provides a theoretical basis and practical guidance for the design of tunnel excavation and support with similar engineering background.
The paper “Investigation of deformation mechanisms in intersecting sections of interchange tunnels using the negative Poisson’s ratio anchor excavation compensation method” authored by Songyuan LIU, Yadong MAO, Zhifeng DU, Liang GAO, Shiding CAO, Manchao HE, Zhigang TAO. Full text of the paper: https://doi.org/10.1007/s11709-025-1179-2.