地震作用下海底场地地震动效应研究

Seismic Responses of Seafloor Site Under Earthquake

通过ABAQUS运用一维时域显式积分方法,采用6条地震波,对某海域两个油田场地进行地震反应分析,得到在不同强度地震动时海底场地的反应,并且对两个海底场地按照现行规范进行场地类别划分.结果表明,海底波的反应谱特征明显区别于陆地波;随着基岩输入地震动强度的增大,其反应谱峰值逐渐增大,且地震动强度主要影响反应谱的高频段,对低频段的影响有限;而海底场地对地表峰值加速度的放大作用逐渐减小,呈非线性变化.现有的针对陆上地震抗震设计参数的选取对海域场地适用性较差,有必要针对海底场地展开相应的研究.

Based on ABAQUS,a one-dimensional time domain explicit integration method was applied to analyze the seismic response of two oil field sites under six seismic waves.The influence of seafloor site condition on the site response was obtained under different earthquake intensities,and the category of two seafloor sites was classified according to current codes.The results show that the response spectra of seafloor waves are clearly distinguished from those of terrestrial waves.With the increase of earthquake intensity,the peak value of response spectrum increases gradually.However,earthquake intensity mainly affects the high frequency band of the response spectrum,and only has a limited impact on the low frequency band.At the same time,the amplifying effect of seafloor soil on the surface peak acceleration of the ground motion decreases gradually and changes nonlinearly.The existing seismic design parameters for land could not apply to seabed,so it is necessary to carry out corresponding researches on it.