泉州盆地地震效应特征的一维等效线性和二维非线性分析的比较  

Comparison between One-dimensional Equivalent Linear and TwoDimensional Nonlinear Analysis on Seismic Effect of Quanzhou Basin

作　　者：董菲蕃[1,2] 陈国兴[1,2] 金丹丹[1,2] 

机构地区：[1]南京工业大学岩土工程研究所,南京210009 [2]江苏省土木工程防震技术研究中心,南京210009

出　　处：《防灾减灾工程学报》2014年第2期154-160,共7页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家科技支撑计划项目(2009BAK55B00)资助

摘　　要：采用等效线性动粘弹性模型描述土的动力非线性特性,基于一维等效线性波传法,对泉州盆地地震效应进行了分析;同时,采用修正Martin-Seed-Davidenkov动粘弹塑性模型描述土的动力非线性特性,对泉州盆地非线性地震效应进行了大尺度二维精细化有限元分析,研究了地形地貌和土层横向不均匀性对地震效应的影响。将两种分析结果进行对比,结果表明：①随着基岩输入地震动强度增大,地表峰值加速度PGA放大效应总体呈现减小趋势,中震与小震、大震与小震的地表PGA放大系数之比依次为0.83~0.99、0.72~0.97;②该盆地Ⅲ类场地处,基岩、地表起伏不大,且土层横向分布较均匀,两种方法计算得到的地震效应特征类似;基岩或地表起伏剧烈、土层横向分布明显不均匀的Ⅱ类场地上,二维非线性分析给出的地表PGA放大系数明显大于一维等效线性结果,两种方法得到的地表加速度反应谱及PGA随土层深度的变化特征存在显著差异,二维非线性分析给出的地表加速度反应谱大多呈现双峰甚至多峰现象,且PGA在土层特定深度处存在聚集效应,使PGA随土层深度的变化呈现非单调性。Adopting the equivalent linear visco-elastic constitutive relations of soils,one-dimensional（1D）analysis models of Quanzhou basin were established using equivalent linear method. Also,large-scale refined two-dimensional（2D）FE nonlinear analytical models were established for the sake of contrast,in which the modified Martin-Seed-Davidenkov viscous elastic-plastic constitutive relations were taken to simulate the dynamic characteristics of soils.Considering the inhomogeneity of ground soils and fluctuation of topography and bedrock surface,the seismic site effect was studied.Comparison between 1Dand 2Dmodels indicates that：1）the peak ground acceleration（PGA）magnification effects show a trend of decrease as the seismic intensity of input ground motion increases.The PGA magnification ratios of moderate earthquake to small earthquake and major earthquake to small earthquake are 0.83-0.99and 0.72-0.97respectively.2） The characteristics of seismic effect analyzed by the two methods are similar to each other when on the III sites.However,the 2Dnonlinear analytical models show a more obvious seismic amplification effect caused by fluctuation of bedrock surface and topography on the II sites.Also,there are significant differences in surface acceleration response spectrum and variations of PGA with depth by the two analytical methods.The acceleration response spectra of surface show a doublepeak or multi-peak phenomenon.Besides,the PGA displays a non-monotonic decreasing characteristic with depth and greater focusing effects of some particular soil layers by the 2Dmodels.

关 键 词：盆地地震效应 一维等效线性波传法 二维非线性有限元法 地表与基岩起伏 土层横向非均匀性 

分 类 号：TU43[建筑科学—岩土工程]