岩土参数空间变异性等效模型适用性研究

Study on Applicability of Equivalent Model of Spatial Variability of Geotechnical Parameters

岩土参数的变异性是边坡稳定性分析中的重要组成部分,不考虑岩土参数的空间变异性高估了岩土参数的内在变异性,导致分析结果偏于保守.通过对岩土参数空间变异性模拟分析,研究了空间变异性等效模型在边坡可靠度分析中的适用性.提出了空间效应评价指标e来定性估计等效模型对边坡可靠度分析结果的影响:当滑面平均倾角小于e时,分析结果偏于冒险;当滑面平均倾角大于e时,分析结果偏于安全.提出了考虑边坡空间效应和尺度效应的评价指标λ来评价其空间变异性等效模型对边坡可靠的影响程度:随λ增加,基于等效模型和各向异性模型的分析结果相对误差增大.通过工程算例验证了所提出的评价指标的合理性.

The variability of geotechnical parameters is an important part of slope stability analysis.Ignoring the spatial variability of geotechnical parameters overestimates the inherent variability of geotechnical parameters,which leads to the conservative analysis results.Through the simulation analysis of spatial variability of geotechnical parameters,the applicability of equivalent model of spatial variability in slope reliability analysis was studied.A spatial effect evaluation index e was proposed to qualitatively estimate the influence of equivalent model on the results of slope reliability analysis.When the average dip angle of the slip surface is less than e,the analysis results tend to be risky.When the average dip angle of the sliding surface is greater than e,the analysis results tend to be safe.The evaluation indexλconsidering the spatial effect and scale effect of slope is put forward to evaluate the influence of its spatial variability equivalent model on slope reliability.With the increase ofλ,the relative error of analysis results based on equivalent model and anisotropic model increases.The rationality of the proposed evaluation index is verified by an engineering example.