【摘要】 利用实验资料研究了中国常规土类动剪切模量比及阻尼比随剪应变变化非线性关系的不确定性问题,包括典型应变下分布形态、概率统计指标以及不同概率水准下变化范围和规律。以中国17个省份42个城市和地区588组土样实验为基础数据,对8个典型剪应变进行的动剪切模量比及阻尼比不确定性的概率进行分析,结果表明:常规土类动剪切模量比和阻尼比的变异性以偏态分布为主,其概率统计指标呈现良好规律;各种土类动剪切模量比及阻尼比的标准差和变异系数都很大,而标准差最大值恰出现在土层地震反应计算的敏感区间内;各种土类动剪切模量比及阻尼比的外包线与其95%参考值都有较大差别,体现了实验结果显著的离散性;动剪切模量比的变异系数随剪应变而明显增大,阻尼比的变异系数随剪应变的增大而显著减小;大应变时动剪切模量比不确定性大,而小应变时阻尼比离散显著;阻尼比的变异系数要明显大于动剪切模量比的变异系数,表明阻尼比具有更大的不确定性。更多还原

【Abstract】 By using the test data,the uncertainty of the dynamic modular ratio G/Gmax and damping ratio λ versus dynamic shear strain γ for the conventional soils in China is studied.The characteristics of the uncertainty distribution,the probability indexes as well as the range of G/Gmax and λ for the typical strains under different probabilities are presented.Based on 588 groups of test results from 42 cities and districts in 17 provinces in China,the uncertainty of the modular ratio and damping ratio versus 8 typical shear strains is analyzed.The results indicate that most of the uncertainty distribution of G/Gmax and λ is abnormal and that the statistic indexes for the probability are regular.The standard deviation and the variation coefficient of G/Gmax and λ are both significant,and meanwhile the maximum of the standard deviation just appears in the sensitive range for the seismic analysis of soil layers.The 95% reference values of G/Gmax and λ are quite different from the envelopes of G/Gmax and λ for all types of soils.The variation coefficients of G/Gmax increase with the increase of the shear strain,but the variation coefficients of λ decrease with the increase of the shear strain.The uncertainty of G/Gmax is obvious at the large strain,while that of λ is obvious at the small strain.The variation coefficients of λ are larger than those of G/Gmax,indicating the uncertainty of the dynamic damping is more remarkable than the dynamic modulus.更多还原