高速铁路隧道围岩参数空间变异性的力学响应分析

 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。

Stochastic analysis of surrounding rock behavior of high speed railway tunnel considering spatial variation of rock parameters

In the high speed railway tunnel，the mechanical behavior of surrounding rock is greatly affected by the spatial variation of rock parameters. A non-intrusive stochastic finite difference model was thus proposed to explore the influence of spatial variation of parameters of surrounding rock. The stratigraphic structure of the tunnel was simulated with Monte-Carlo methods. The proposed model was applied to analyze the mechanical behavior of the tunnel after excavation，with emphasis on the impact of parameter variation and spatial correlation. The mechanical behaviors influenced are the deformation characteristics of the surrounding rock，the mode of the plastic zone development，and the morphology of the ground surface settlement. The proposed model was compared with the deterministic model. The low-intensity structural load was found to dominate the mechanical behaviors. The anisotropic behavior is significant in the tunnel structure after excavation. The sensitivity and nonlinearity of the performance function were analyzed. The distributional and transitional effect of performance function was provided.