考虑地层变异性和土体参数变异性的边坡可靠度分析

发布时间：2018-02-12 04:11

本文关键词： 边坡可靠度地层变异参数固有变异　出处：《岩土工程学报》2017年06期 　论文类型：期刊论文

【摘要】：现有边坡可靠度分析大多数只考虑土体参数的固有变异性,而忽略了地层变异性的影响。为此,提出了同时考虑地层变异性和土体参数固有变异性的边坡可靠度分析方法,利用耦合马尔可夫链模拟地层分布,采用基于乔列斯基分解的中点法离散土体参数随机场,采用有限元强度折减法计算边坡安全系数,通过蒙特卡洛法模拟进行边坡可靠度分析。利用澳大利亚珀斯市钻孔资料,以边坡可靠度问题为例阐明了同时考虑地层变异性和土体参数固有变异性的重要性,研究了钻孔布置方案对边坡可靠度的影响规律,结果表明:提出的方法能够有效地反映地层变异性和土体参数固有变异性对边坡可靠度的影响。当钻孔数目较少时,模拟的边坡土体类型分布与真实边坡土体类型分布相差较大,此时忽略地层变异性将导致边坡可靠度不精确的估计结果。钻孔布置方案对边坡失效概率和安全系数有明显的影响,钻孔应尽可能多的布置在边坡关键影响区域。边坡失效概率和安全系数统计量与钻孔数目并不呈单调关系,但是随着钻孔数目的增加,边坡失效概率和安全系数统计量逐渐收敛至"精确解"。
[Abstract]:Most of the existing slope reliability analysis only considers the inherent variability of soil parameters, but neglects the influence of stratigraphic variability. Therefore, a slope reliability analysis method considering both the formation variability and the inherent variability of soil parameters is proposed. The coupling Markov chain is used to simulate the stratigraphic distribution, the midpoint method based on Cholesky decomposition is used to discretize the random field of soil parameters, and the finite element strength reduction method is used to calculate the slope safety factor. The reliability analysis of slope is simulated by Monte Carlo method. The importance of considering both the formation variability and the inherent variability of soil parameters is illustrated by using the drilling data of Perth, Australia, and taking the slope reliability as an example. The influence of borehole layout on slope reliability is studied. The results show that the proposed method can effectively reflect the influence of formation variability and inherent variability of soil parameters on slope reliability. The distribution of simulated slope soil type is quite different from that of real slope soil type. The failure probability and safety factor of the slope are obviously affected by the borehole layout scheme, which will result in the inaccurate estimation of slope reliability if the formation variability is ignored. Boreholes should be arranged as much as possible in the critical impact areas of the slope. The probability of slope failure and the statistics of safety factor are not monotonous related to the number of boreholes, but with the increase of the number of boreholes, Slope failure probability and safety factor statistics converge to exact solution.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;武汉大学水利水电学院;
【基金】：国家杰出青年科学基金项目(51225903) 湖北省自然科学基金创新群体项目(2014CFA001) 国家自然科学基金项目(51579190,51528901)
【分类号】：TU43

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