Wang Ruqin, Wang Zhichao, Fan Wenxuan
School of Highway, Chang'an University, Xi'an, 710064, China.
Chang'an Dublin International College of Transportation at Chang'an University, Chang'an University, Xi'an, 710018, China.
Sci Rep. 2025 May 28;15(1):18608. doi: 10.1038/s41598-025-03078-5.
The Center Diaphragm Method (CDM) fits shallow tunnels with unsymmetrical pressure, large cross-section and adverse geological conditions. However, the curvature of the center diaphragm, as the key parameter, is currently determined empirically. This paper explored the interaction between the support system and the surroundings in CDM-constructed tunnels under different curvatures of the center diaphragm. The theoretical analysis was conducted by establishing a mechanical model of the primary lining-upper center diaphragm double-arch support structure, which takes covering depth, unsymmetrical pressure angle, and temporary support location as variable parameters. Therefore, the relationship between the curvature of the center diaphragm and the internal forces of the support structure was obtained, and the validity of this model was verified. Moreover, three-dimensional numerical models were established with Midas GTX NX to investigate construction performance under various curvatures. The results showed that as the curvature of the center diaphragm increased, the crown settlement of the leading pilot tunnel increased and the growth in the compressive stress of the primary support caused by the dismantling of the center diaphragm was weakened, and the straight center diaphragm bore less stress than the curved ones. These results provide reference for similar projects and assist in improving tunnel CDM application.
中心隔板法（CDM）适用于具有不对称压力、大断面和不良地质条件的浅埋隧道。然而，作为关键参数的中心隔板曲率目前是凭经验确定的。本文探讨了在中心隔板不同曲率情况下，采用CDM法施工的隧道中支护体系与周围环境之间的相互作用。通过建立以覆盖层深度、不对称压力角和临时支护位置为可变参数的初期衬砌 - 上部中心隔板双拱支护结构力学模型进行理论分析。由此得到了中心隔板曲率与支护结构内力之间的关系，并验证了该模型的有效性。此外，利用Midas GTX NX建立三维数值模型，研究不同曲率下的施工性能。结果表明，随着中心隔板曲率的增大，先行导洞的拱顶沉降增大，中心隔板拆除引起的初期支护压应力增长减弱，且直中心隔板承受的应力比曲中心隔板小。这些结果为类似工程提供参考，有助于改进隧道CDM法的应用。
