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为了给兰州乃至西北地区的地震安全性评价和重大工程抗震设计提供参考,在兰州地区选取4个不同类别场地,完成由10家单位参加、使用不同仪器剪切波速现场测试误差专项实验,研究该地区剪切波速实测误差分布规律,讨论测试误差对地表加速度反应谱影响的统计特征,并给出该地区剪切波速测试误差评价。结果表明:兰州地区各单位剪切波速测试误差具有明显规律性,测试误差绝大部分符合标准正态分布,且误差大小不随深度和场地类别而改变;兰州地区波速测试水平优于全国平均水平,Ⅰ类、Ⅱ类和Ⅲ类场地的剪切波速测试精度较高,偏差较小,其平均标准差可以定为10%;就兰州地区而言,其1倍波速测试标准差引起PGA最大偏差为25%,2倍标准差为50%;给定波速测试误差下反应谱变化程度与输入波形相关,输入波频率成分与场地频率成分接近的地震输入下,误差影响较大,反之则影响较小。
In order to provide reference for earthquake safety assessment and seismic design of major projects in Lanzhou and even Northwest China, four different types of sites were selected in Lanzhou area. Ten units participated in the experiment, The distribution of the measured shear wave velocity error in the region is discussed. The statistical characteristics of the influence of the test error on the surface acceleration response spectrum are discussed. The evaluation of the shear wave velocity error in this region is also given. The results show that the shear wave velocity error of all units in Lanzhou has obvious regularity, most of the error in the test is in accordance with standard normal distribution, and the error does not change with the depth and the type of site. The wave velocity test in Lanzhou is better than the national average, The shear wave velocity of Class I, II and III venues has higher precision and less deviation, and the average standard deviation can be set at 10%. For Lanzhou, the maximum deviation of PGA caused by the standard deviation of one-times wave velocity 25% and twice the standard deviation is 50%. The variation of the response spectrum under a given wave speed test error is related to the input waveform. The input error frequency is greatly affected by the input of the frequency components of the input wave and the frequency components of the site, otherwise the influence is small .