考虑参数空间变异性的隧道结构变形分析简化方法

土体参数具有空间变异性是被广泛接受的,而这种变异性对岩土中结构性能有着重要的影响。随机场理论是一种常用的用来模拟土体参数空间变异性的方法。基于随机场理论,以土体弹性模量的空间变异性为切入点,采用蒙特卡罗方法和有限差分模拟计算相结合的方法,开展隧道水平收敛的随机分析。在大量蒙特卡罗计算基础上,提出了3种简单易用的简化考虑空间变异性的方法,分别为参数折减法、放大系数法和可靠度分项系数标定法。经过对计算结果的统计分析,给出了在土体弹性模量的水平、竖向相关距离及其变异系数的不同组合下3种简化考虑方法的建议值。提出的简化方法可以为空间变异性研究应用到实际工程提供一定的参考。

Simplified methods for deformation analysis of tunnel structures considering spatial variability of soil properties

The spatial variability of soil properties is widely accepted,and the response of a geo-structure can be significantly affected by the spatial variability of the surrounding soil mass.The random field theory is a popularly used method to simulate the spatial variability of soil properties.The stochastic analysis of horizontal convergence of tunnel is carried out using the random field difference method considering the spatial variability of Young’s modulus.The random field difference method is combined with the Monte Carlo method and finite difference simulation based on random field theory.A large number of Monte Carlo simulations are adopted in the proposed random field difference method.Meanwhile,three simple and easy-to-use methods for the spatial variability of soil are proposed:reduction factor method,amplification factor method and reliability partial factor calibration method.Based on the statistical analysis of the calculated results,the suggested values of three simplified analysis methods under different combinations of the horizontal scale of fluctuation,the vertical scale of fluctuation and the coefficient of variation are given.This study may provide references for the application of spatial variability research to practical geotechnical engineering.