摘要
准确地确定岩土设计参数统计特征值诸如均值、标准差是岩土工程可靠度分析与设计的重要前提。在满足岩土设计参数统计特征值计算精度条件下,文中提出了岩土工程最小勘探数据量的确定方法,定义了相对误差和相对变异性指标衡量岩土设计参数统计特征值计算准确性。系统地分析了静力触探试验数据量对砂土有效内摩擦角统计特征值计算精度的影响,并且根据相对误差和相对变异性指标确定了静力触探最小勘探数据量。研究结果表明,由静力触探试验间接估计砂土有效内摩擦角时均值相对误差较低,砂土有效内摩擦角相对变异性指标随静力触探试验数据量的增加而降低,即由认知不足引起的不确定性占总变异性的比值随静力触探试验数据量的增加而减小;当砂土有效内摩擦角容许相对变异性指标小于0.2时砂土有效内摩擦角在最大变异(COV=20%)与最小变异性(COV=5%)范围内,满足预定要求所需的最小静力触探试验数据量为10~100;若容许相对变异性指标小于0.3,所需的最小静力触探试验数据量为5~43。此外,间接估计岩土设计参数时经验回归模型不确定性对最小勘探数据量有显著影响。静力触探试验最小勘探数据量随经验回归模型不确定性的增大而增加,在确定岩土设计参数统计特征值时应尽量广泛收集勘探数据并选择精度较高的计算模型。
Accurate determination of statistical characteristic values(e.g.mean and standard deviation)of geotechnical design parameters is an important prerequisite for geotechnical reliability analysis and design.In this paper,under the condition of satisfying the accuracy of statistical design of geotechnical design parameters,a new method is proposed to determine the minimum test data quantity of geotechnical engineering.The relative error and relative variability index are defined to measure the accuracy of the statistical characteristics of geotechnical design parameters.The influence of the static cone penetration test data on the calculation accuracy of the statistical characteristic value of effective internal friction angle of sand soil is systematically analyzed.Moreover,the minimum cone penetration test data quantity is determined based on the relative error and relative variability index.The results show that the relative error of mean value of internal friction angle of sand estimated indirectly from static cone penetration test is small.The relative variability index of sand internal friction angle decreases with the increasing in the data quantity of static cone penetration test.The ratio of uncertainty caused by insufficient cognition to total variability decreases with the increasing data quantity of static cone penetration test.When the allowable relative variability is less than 0.2,the variability of sand internal friction angle is in the range of 5%and 20%COV,which satisfies the predetermined requirement of minimum static cone penetration test data quantity of 10-100.If the relative variability is allowed to be less than 0.3,the minimum static cone penetration test data quantity is 5-43.In addition,when estimating the geotechnical parameters,the uncertainty of empirical regression model has a significant influence on the minimum data quantity.The minimum data quantity of static cone penetration test increases with the increasing uncertainty of empirical regression model.Therefore,the test data should b
作者
田密
盛小涛
TIAN Mi;SHENG Xiao-tao(School of Civil Engineering,Architecture and Environment,Hubei University of Technology,Wuhan,Hubei430068,China;Key Laboratory of RockMechanics in Hydraulic Structural Engineering of Education Ministry,Wuhan University,Wuhan,Hubei430072,China;Key Laboratory of GeotechnicalMechanics and Engineering of Ministry ofWater Resources,Yangtze River Scientific Research Institute,Wuhan,Hubei430010,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2019年第A01期400-408,共9页
Rock and Soil Mechanics
基金
国家自然科学基金项目（No.51579093）
武汉大学水工岩石力学教育部重点实验室开放基金项目（No.RMHSE1905）
湖北工业大学博士科研启动基金项目（No.BSQD2017034）~~
关键词
勘探数据量
岩土参数
统计特征值
变异性
模型不确定性
test data quantity
geotechnical parameters
statistical characteristic values
variability
model uncertainty
