中文摘要：

采用随机场模型能够有效地模拟围岩参数的空间变异性。文章将局部平均随机场理论、有限差分法和Monte-Carlo模拟结合在一起,得到了Monte-Carlo随机有限差分法,基于该方法编制了可考虑围岩空间变异性的隧道结构可靠度计算程序;并将围岩密度、弹性模量和内摩擦角等参数视为三维正态随机场,研究了围岩的竖向与水平向相关距离的变化对隧道结构可靠度的影响。计算结果表明,围岩空间变异性会显著影响隧道结构的可靠度,为了获得更为经济合理的支护方案,在支护设计时考虑围岩参数的空间变异性很有必要;围岩竖向或水平向相关距离的增大均会引起隧道结构失效概率的增加,但影响程度不同;隧道结构失效概率对围岩竖向空间变异性更加敏感,故在工程勘察费用较少时,可考虑将勘察费用更多地投入到竖向相关距离的勘测,水平向相关距离可参考已有经验数据取值。

英文摘要：

A random field model can be used to effectively simulate the spatial variability of surrounding rock.In this paper,the local average random field theory,finite difference method,and Monte-Carlo simulation are combined,and the Monte-Carlo random finite difference method is developed.Based on this method,a calculation program for the structural reliability of a tunnel considering the spatial variability of surrounding rock is worked out,and the influence of the rock＇s vertical and horizontal correlation distance on the tunnel＇s structural reliability is also researched by regarding the rock density,elastic module,and internal friction angle as 3D normal random fields.The results show that： to obtain a more economical and reasonable support scheme,it is necessary to take the spatial variability of surrounding rock into account in the design,since it has a significant effect on the tunnel＇s structural reliability; the tunnel failure probability increases with the increase of the vertical or horizontal correlation distance,but there is a greater effect from the vertical spatial variability.So once the geotechnical investigation fee is limited,the majority of the cost can be focused on a survey of the vertical correlation distance.