边坡稳定分析中岩土参数置信水平取值探讨

发布时间：2018-02-19 21:12

  本文关键词： 岩土参数 小样本 置信水平 变异性 边坡稳定　出处：《铁道科学与工程学报》2017年04期 　论文类型：期刊论文

【摘要】：岩土工程勘察规范统一使用95%保证率单侧置信下限值作为土体强度指标标准值,用于补偿小样本抽样带来的安全风险,但在变异性较大时可能造成过盈估计。基于均值相同的小、中、大变异水平强度参数总体,采用固定容量的小样本多批次随机抽样方法,构建不同保证率的c和φ标准值分布空间,分析与之映射的均质土坡安全系数结果空间的分布特征,讨论等安全系数原则下参数保证率与土体变异水平的内在关系。研究结果表明:安全系数的离散程度与土体变异性和参数置信水平均呈正相关,采用95%置信水平统一值将导致对变异性较大土体的边坡安全程度估计过低;以安全系数结果空间的分位值相等为控制条件,提出土体变异性增大可相应降低参数置信水平的建议。
[Abstract]:In geotechnical engineering survey code, 95% guarantee rate one-sided confidence lower limit value is used as the standard value of soil strength index, which is used to compensate for the safety risk caused by small sample sampling. However, the interference estimation may be caused when the variability is high. Based on the small, medium and large variation level strength parameters of the same mean, the method of multi-batch random sampling of small samples with fixed capacity is adopted. The distribution space of c and 蠁 standard values of different guarantee rates is constructed, and the distribution characteristics of the result space of safety factor of homogeneous soil slope mapped with it are analyzed. This paper discusses the intrinsic relationship between the guarantee rate of parameters and the variation level of soil under the principle of equal safety coefficient. The results show that the dispersion degree of safety factor is positively correlated with the variability of soil and the confidence level of parameters. Using the unified value of 95% confidence level will lead to the overestimation of the slope safety degree of the high variability soil mass, and take the equal quantile value of the result space of the safety factor as the control condition. It is suggested that the increase of soil variability can reduce the confidence level of parameters.
【作者单位】： 西南交通大学土木工程学院;高速铁路线路工程教育部重点实验室;
【基金】：国家重点基础研究发展规划(973计划)项目(2013CB036204)
【分类号】：TU43
，

本文编号：1517988