【摘要】 利用武汉地区地震安全性评价报告中共振柱实验获得的1 403组土动力非线性参数数据,统计出武汉地区7种不同土性不同埋深的土类在8个典型应变下的动剪切模量比和阻尼比的平均值。根据2个工程场地在实验值、统计平均值、规范值输入下的土层地震反应分析结果,对比分析了3种土动力参数值对场地地震动参数的影响,对所给出的平均值的合理性进行分析。结果表明,与规范值相比,统计平均值与实验值的土层地震反应分析结果基本一致,计算结果真实合理,可供武汉地区场地土动力学参数实验数据缺乏时参考使用。更多还原

【Abstract】 In recent years,seismic safety evaluation has been conducted at many engineering sites in the Wuhan area in which the dynamic nonlinear parameters of various soils were obtained.These data show diversification of soil patterns and a reasonable layout of space.According to factors such as the soil’s nature,geological formation,and physical and mechanical properties,the strata are classified roughly as silty clay,clay,silt,silty sand,silty and fine sand,fine sand,and coarse sand.Among these categories,750 groups of silty clay are identified in addition to 244 groups of clay,63 groups of silt,69 groups of silty sand,93 groups of silty and fine sand,153 groups of fine sand,and 31 groups of coarse sand.Considering the influence of depth,or confining pressure,these groups are further divided.For silty clay,373 groups are classified at 0~10m,272 at 10~20m,79 at 20~30m,and 26 at 30~50m.For clay,132 groups are classified at 0~10m,96 at 10~20m,and 16 at 20~30m.For silt,23 groups are classified at 0~10m,29 at 10~20m,and 11 at 20~40m.For silty sand,34 groups are classified at 0~20mand 35 at 20~50m.For silty and fine sand,22 groups are classified at 10~20m,64 at 20~40m,and 7at 40~60m.For fine sand,39 groups are classified at 0~20 m,97 at 20~40 m,and 17 at 40~60 m.For coarse sand(medium sand and coarse sand),13 groups are classified at 15~30mand 18 at 30~50m.The dynamic nonlinear parameters of soil samples were tested using a free vibration column apparatus.The dynamic nonlinear parameters of 1403 groups of soil samples from the seismic evaluation reports of the Wuhan area were used to obtain the statistical mean values for the dynamic shear modulus ratios and the damping ratios of seven types of soil with varying depths under eight typical strains.To analyze the rationality of the statistical mean values,two typical engineering sites are chosen in which seismic response analysis is conducted.On the basis of the results,the influences of actual test values and the statistical mean standard values of code DB001-94 on ground motion parameters are compared and analyzed.In addition,the rationality of statistical mean values is demonstrated.Compared with the results of the code,the seismic response analysis results of the statistical mean values are closer to the results obtained using actual test values.Under the conditions of moderate and strong earthquakes,certain differences are noted between the results of the code and the actual test values.These differences cannot be ignored;the statistical mean values are believable and reasonable.These values can be used as references in the case of insufficient soil dynamic parameters at the Wuhan sites.However,the statistical values differ significantly when using different dynamic parameters at the same site.Therefore,for seismic safety analysis of major projects,soil sampling,and dynamic parameter testing must be conducted in accordance with the requirements of relevant codes.更多还原