【摘要】 以渤海PL19-3油田工程场地为研究对象,利用钻探和剪切波速实测资料,根据中国规范GB50011-2001、美国规范FEMA-NEHRP和欧洲规范EC8,进行场地类别研究;通过地震动效应分析,得到海底表层软弱土对峰值加速度和反应谱的影响。结果表明,现行规范中的场地土类型划分标准是针对陆地场地土特征的,不能反映覆盖较厚的海底淤泥层的特征;海底表层软弱土对地震动加速度的幅值和频谱的影响非常明显,其对峰值加速度的放大倍数较高,但受土的非线性变形影响,随着地震动输入的增大,其放大倍数呈非线性降低,软土场地使得加速度反应谱谱形变宽,特征周期变大。本文的结果为开展海洋工程抗震标准、海域地震区划研究积累了相关基础资料。更多还原

【Abstract】 The site of oilfield PL19-3 in Bohai is studied in this paper.According to the Chinese Code GB50011-2001,the America Code FEMA-NEHRP and Europe Code EC8,we use the shear wave velocity and borehole data to study the site classification for soft soil site in Bohai seabed.The site seismic effect is analyzed and the influence of the soft soil of seabed on the design ground motion parameters are discussed.The results show that (1) the site classification in active Codes only fit to the land site,it can’t represent the real characteristics of the thicker silt layer of seabed;(2)the soft soil of seabed surface layer puts a remarkable effect on the magnitude and spectrum of the ground motion: the acceleration is magnified significantly due to the nonlinear deformation of the soil and the amplification factor is reduced nonlinearly with the increase of ground motion input;(3)the spectrum is broadened and the characteristic period is extended.The study will put forward the correlate study on the seismic technical codes and design criterion of the oceanic engineering in China.Furthermore,the results of the paper can provide the relate basic data for the seismic design criterion in oceanic engineering and a future seismic zoning of Chinese sea area.更多还原