考虑参数空间变异性的非均质边坡可靠度分析

Reliability Analysis of Heterogeneous Slopes Considering Spatially Variable Soil Properties

考虑土体参数空间变异性的非均质边坡最危险滑动面存在一定的空间变异性,导致边坡存在多种潜在失效模式。为有效解决含多失效模式的边坡可靠度问题,提出了非均质边坡可靠度分析的多重随机响应面法,并以一个含水平软弱夹层的边坡可靠度分析为例验证了提出方法的有效性,同时探讨了水平软弱夹层及其位置不确定性对边坡可靠度的影响,调查了单重响应面法分析考虑参数空间变异性非均质边坡可靠度问题的有效性。结果表明:多重随机响应面法为解决考虑多参数空间变异性的低概率水平非均质边坡可靠度问题提供了一个重要的工具,然而单重响应面法会高估边坡失效概率,导致偏保守的边坡设计方案。此外,水平软弱夹层对边坡稳定性、失效路径及可靠度均具有重要的影响,相比之下软弱夹层位置不确定性对边坡可靠度的影响较小。

The critical slip surface with the minimum factor of safety（FSmin）of a heterogeneous slope varies spatially when the spatial variability of soil properties is considered,which may induce numerous potential failure mechanisms existing in the slope.To effectively solve the slope reliability problems involving numerous potential failure mechanisms,a multiple stochastic response method（MSRSM）is proposed for reliability analysis of heterogeneous slopes.The reliability of a heterogeneous slope with a horizontal weak layer is investigated to demonstrate the effectiveness of the proposed approach.The effects of the horizontal weak layer and its uncertainty of location distribution on the slope reliability are addressed.The capacity of the traditional single response surface method in reliability analysis of heterogeneous slopes with spatially variable soil properties is also explored.The results indicate that the proposed approach can effectively evaluate the reliability of heterogeneous slopes in spatially variable soils.In contrast,it leads to an overestimation of the failure probabilities and relatively conservative slope designs using the single response surface method.Additionally,the horizontal weak layer has a significant influence on the slope stability,weakest failure path and slope reliability,while the effect of the uncertainty of location distribution is slight on the slope reliability.