土坡稳定分析中考虑参数变异水平的分项系数取值  

Discussion on the value of partial factors considering variation level of geotechnical parameter in slope stability analysis

作　　者：李昂[1,2] 罗强[1,2] 张文生[1,2] 蒋良潍[1,2] 张良[1,2] LI Ang;LUO Qiang;ZHANG Wensheng;JIANG Liangwei;ZHANG Liang

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]高速铁路线路工程教育部重点实验室,四川成都610031

出　　处：《铁道科学与工程学报》2019年第2期341-350,共10页Journal of Railway Science and Engineering

基　　金：国家重点基础研究发展计划(973计划)项目(2013CB036204)

摘　　要：岩土参数变异性大导致可靠指标离散性高,仅用1组分项系数难以保证土工结构可靠性达到目标可靠度。将土体强度参数变异性划分为小、中、大3个水平,以现有规范规定安全系数为控制指标,对常见铁路路堤边坡目标可靠度进行校准,确定目标可靠指标为2.3;运用验算点法计算分项系数,讨论几何和强度参数对分项系数影响规律,通过统计分析及标定得到了对应3种变异水平的分项系数推荐值。研究结果表明:土体强度参数变异性是影响分项系数取值的主导因素,强度参数均值和坡高次之,坡率的影响较为微弱;为使强度参数变异性不同的边坡达到一致的可靠度,提出了分项系数应与参数变异水平相适应的取值原则,给出了小、中、大变异水平对应的抗力项和荷载项分项系数(γR1,γR2,γS)推荐值分别为(0.75, 0.95; 1.02),(0.55, 0.90; 1.06)和(0.40, 0.80; 1.10)。Large variation of geotechnical property result in large discrete of engineering reliability index, reliability index of engineering can not achieve our goals by single partial factors, The variability of soil strength parameter was divided into three grades: small, medium and large, a series of simple slope models with a variety of geometric and intensity parameters was constructed based on the calibration method and carrying out stable reliability calculation, and determine the target reliability index is 2.3. Calculating the partial factors by design point method, the influence of soil strength parameters and slope geometric parameters on the partial factor was discussed, and the recommended values of the partial factors under the three variation levels were calculated by the design point method. Study shows that the coefficient of variation of soil strength parameters is the dominant factor for the partial factors, mean value of soil strength parameters and slope height also have a certain impact on the partial factors, the effect of slope rate on partial factors is small;In order to make the slope with different variation of strength parameters to achieve consistent reliability, value principle is proposed partial factors should be adapted to the level of parameters variation, and the recommended values of the resistance term and the load term of the partial factors with small, medium, and large parameter variation level are (0.75, 0.95, 1.02),(0.55, 0.90, 1.06),(0.40, 0.80, 1.10).

关 键 词：土坡稳定分析 参数变异水平 分项系数 目标可靠指标 验算点法 

分 类 号：U213.13[交通运输工程—道路与铁道工程]