摘要
针对土层非均匀分布的苏州城区凹陷沉积场地,采用黏弹性人工边界模拟无限域场地的边界,基于ABAQUS建立大尺度二维有限元模型,分析了加速度峰值、位移峰值、频谱等地震动参数特征,探讨了凹陷沉积土层对地震效应的影响.结果表明:凹陷沉积地震动响应呈现较大的空间差异性,局部位置地表加速度放大效应明显;苏州城区场地敏感周期段为0.20~0.70 s,与水平均匀场地相比,凹陷沉积场地地表反应谱沿横向变化较大,越靠近地表,反应谱谱峰越向长周期方向偏移;由于地震波在局部区域聚焦,凹陷沉积场地PGA值沿深度方向呈起伏变化现象;沿水平方向的PGD随土层深度增加呈非单调递减,且与输入地震动频谱特性相关.大尺度二维模型一定程度上能合理反映微地形起伏、土层分布对地震波传播过程的影响.
For the sedimentary sites of Suzhou urban depression with non-uniform distribution of soil layers, a large-scale two-dimensional(2 D) FE analytical model for concave sedimentary soil layers in Suzhou city was established based on the computing cluster platform of ABAQUS. The viscoelastic artificial boundary was proposed for simulating the boundary problem of infinite field, and the main characteristics of peak acceleration, peak displacement and spectrum were analyzed. The results show that the seismic response of concave sedimentary site presents great spatial difference, and the amplification effect of peak ground acceleration is obvious in some specific positions. The sensitive periods of the urban site of Suzhou city is about 0.20 to 0.70 s. Compared with the horizontal uniform site, the acceleration response spectrum of the concave sedimentary site changes significantly along the horizontal direction, and the corresponding spectrum peak shifts towards the long period direction as it comes close to the ground surface. Because the seismic waves are focused and amplified in some local areas, the PGA values in the concave sedimentary site show ups and downs along the direction of depth. The PGD values along the horizontal direction show non-monotone decreasing with the increasing of soil depth, which is related to the spectral characteristics of input ground motions. To some extent, the large-scale 2 D FE model can reflect the effects of non-uniform distribution of soil layers on seismic wave propagation.
作者
金丹丹
师梦芹
丁文昌
朱姣
JIN Dandan;SHI Mengqin;DING Wenchang;ZHU Jiao(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang,Jiangsu 212013,China;Institute of Geotechnical Engineering,Nanjing University of Technology,Nanjing,Jiangsu 210009,China)
出处
《江苏大学学报（自然科学版）》
EI
CAS
北大核心
2019年第6期706-712,共7页
Journal of Jiangsu University：Natural Science Edition
基金
国家自然科学基金资助项目(51708256)
江苏省青年基金资助项目(BK20150512)
中国博士后科学基金资助面上项目(2016M591785)
关键词
凹陷沉积场地
地震动峰值
频谱特性
人工边界
ABAQUS
concave sedimentary site
peak ground motion
spectral characteristics
boundary condition
ABAQUS
