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针对大断面高速铁路隧道围岩的参数变异性及空间相关性等问题,在随机场理论的基本框架下,将非侵入式随机分析、地层结构模型、有限差分法和蒙特卡洛模拟有机结合,提出考虑围岩参数空间变异性的非侵入式随机有限差分分析模型。运用该模型对隧道开挖后围岩的力学响应进行分析,得到围岩参数空间变异性的2个基本要素:参数变异性和空间相关性,其特征参数的取值变化会直接影响到围岩变形特性、塑性区发展模式以及地表沉降形态。同时与确定性模型的计算结果进行比较,提炼出隧道开挖后围岩参数空间变异性的4种典型工程效应:(1)围岩结构性低强度荷载占优效应;(2)围岩结构空间相关各向异性效应;(3)功能函数敏感性差异及非线性效应;(4)功能函数转变分布类型效应。研究成果为拓展基于空间变异性的高速铁路隧道工程稳健性设计奠定了一定的基础。
According to the parameter variability and spatial correlation of surrounding rock of large-section and high-speed railway tunnels, under the basic framework of random field theory, non-invasive stochastic analysis, stratum structural model, finite difference method and Monte Carlo simulation are combined organically, A non-invasive stochastic finite difference analysis model is proposed to consider the spatial variability of surrounding rock parameters. The model is used to analyze the mechanical response of the surrounding rock after tunnel excavation. Two basic elements of the spatial variability of the surrounding rock parameters are obtained: the parameter variability and the spatial correlation. The change of the value of the characteristic parameter will directly affect the surrounding rock Deformation characteristics, the development of plastic zone and surface subsidence morphology. At the same time, compared with the results of deterministic model, four typical engineering effects of the surrounding rock parameters spatial variability after tunnel excavation are extracted: (1) the dominant low-intensity load of surrounding rock dominates; (2) the surrounding rock structure Spatial Correlation Anisotropy Effect; (3) Functional Function Sensitivity Difference and Nonlinear Effect; (4) Functional Function Transition Distribution Type Effect. The research results lay a solid foundation for expanding the design of robustness of high-speed railway tunnels based on spatial variability.