为精细且高效模拟核电工程中单层衬砌取排水隧洞在复杂荷载下的受力性态，分析其影响要素，基于八叉树离散技术建立隧洞-地基的跨尺度精细模型，联合有限元-比例边界有限元（FEM-SBFEM）耦合分析算法，通过24个工况系统探究地层类型、隧洞内径、隧洞埋深和内水压力4类要素对单层衬砌受力性态的影响规律，并分析各因素间的相关性和潜在数学关系。研究表明： 1）本文方法有效提升了隧洞结构受力分析效率（代表工况可提升34.3%），有助于提高诸如敏感性、易损性等多工况模拟的分析效率； 2）量化了各因素对单层衬砌应力的影响规律，并给出了影响程度的排列顺序，其中，隧洞埋深对压应力影响较大，地层类型和内水压力对拉应力影响较大； 3）采用多项式拟合建议了隧洞内径R与最大埋深Hmax和最大内水压力pmax的潜在数学关系。
In this study, the force behavior of single-layer lined drainage tunnels under complex loads in nuclear power projects is finely and efficiently simulated, and their influencing elements are analyzed. Additionally, a cross-scale fine model of tunnel-foundation is established based on the octree discretization technique, and a coupled finite element-scaled boundary finite element analytical algorithm is employed to systematically examine the influence of four types of elements—the type of stratum, the inner diameter of the tunnel, the depth of the tunnel, and the pressure of the internal water—on the single-layer lining stress pattern based on 24 working conditions. Finally, the correlation and potential mathematical relationships among these factors are analyzed. The results demonstrate the following: (1) The proposed approach effectively improves the efficiency of stress analysis of tunnel structure (34.3% for representative case), being beneficial to analysis efficiency of multi-case simulation such as sensitivity and susceptibility. (2) The influence of various factors on the stress of single-layer lining is quantified, and the influencing order is determined. The tunnel burial depth has a greater influence on compressive stress, while strata type and internal water pressure have a greater influence on tensile stress. (3) The potential mathematical relationships between the inner diameter of the tunnel and the maximum internal water pressure and that between the maximum burial depth and the maximum internal water pressure are clarified using polynomial fitting.
