波速原位测试结果标准差对较深软场地地震反应谱影响初探

Impact of Soil Wave Velocity Test Standard Deviation on Seismic Response Spectrum of a Deep and Soft Site

波速测试结果在工程上的应用越来越重要,但波速测试结果的不确定性一直影响着抗震设计。为了准确地描述这一不确定性,对较深软场地的地震响应进行了计算。采用Shake 2000程序,通过输入不同类型的多种强度的地震波,研究了较深软场地的多种工况下剪切波速测试标准差对地表加速度反应谱和峰值加速度的影响。结果表明,较深软场地上的波速测试标准差对场地的加速度反应谱和峰值加速度基本没有影响;不同地震强度下的反应谱和峰值加速度的变化,基本可以忽略。随着波速测试数据量的增加,本文研究结果还有待进一步的深入与完善。

The test results of shear-wave velocity in engineering are becoming increasingly important, but the uncertainty of the wave test results influence the seismic design all the time. In order to accurately describe this uncertainty, the paper conducts some research on seismic response of the deep-soft sites. By using Shake 2000 program and inputting a variety of ground motions, the authors discuss the ground response spectra and PGA changing rules of deep-soft site. The changing are caused by the variety of shear-wave velocity, which are given by the standard devia- tion of several velocity values. The results are as follows： the standard deviation of the shearwave velocities nearly has no influence on the acceleration response spectra and the PGA of the site; the changes of response spectra and PGA under different seismic intensities can be ignored. With the increase of the shear-wave velocity data, the study would get more accurate and deep results.