【作者】 张炳政；

【导师】 梁建文；

【作者基本信息】 天津大学 ， 结构工程， 2009， 博士

【摘要】 地震震害和理论研究表明局部场地条件对地震动有显著的影响。在滨海、湖泊、河道等沉积地区,透镜体是一种常见的局部场地。本文采用有限元方法研究透镜体对地震动影响的基本规律,分析透镜体宽度、厚度、埋深、刚度、非线性等因素对地震动的影响,对工程抗震设防具有重要的指导意义。研究均匀场地和层状场地中透镜体对地震动的影响问题。比较了含透镜体的均匀场地与不含透镜体的均匀场地(自由场)对地震动影响的差别,着重分析了透镜体宽度、厚度、埋深和刚度、以及地震动频谱等参数对地震响应的影响;比较了含透镜体的层状场地与不含透镜体的层状场地(自由场)对地震动影响的差别,着重分析了层状场地和地震动频谱等参数对地震响应的影响。结果表明,无论均匀场地还是层状场地中透镜体均对地震动有着显著的放大作用,而且层状场地中透镜体比均匀场地中透镜体有着更大的放大作用。研究非线性均匀场地和层状场地中透镜体对地震动的影响问题。利用等效线性化方法计算了含透镜体的非线性均匀场地的地震响应,与不含透镜体的非线性均匀场地(自由场)地震响应进行了比较,并着重研究了均匀场地非线性和输入地震波峰值和频谱对地响应的影响;利用等效线性化方法计算了含透镜体的非线性层状场地的地震响应,与不含透镜体的非线性层状场地(自由场)地震响应进行了比较,着重分析了层状场地非线性和输入地震波峰值和频谱对地震响应的影响。研究表明,无论非线性均匀场地还是非线性层状场地中透镜体均对地震动有着显著的放大作用,场地非线性不仅会降低放大作用的峰值,还会显著提高地震响应反应谱的卓越周期,而且层状场地中透镜体比均匀场地中透镜体有着更大的放大作用。更多还原

【Abstract】 The local site has great effect on the ground motion in earthquake, which is verified by earthquake disaster and theoretical research. The lenticle is one kind of local site in the valley near the sea, lake and river. Finite element method is applied to study the effect of a lenticle on ground motion in this paper, and the influence of different factors such as the width, thickness, depth, material stiffness and material nonlinearity of a lenticle have been analyzed in detail. This research is of great significance for structural earthquake resistance design.The difference between the total response and the free field is compared to study the influence of the a lenticle on the ground motion, and the parameter variations of the frequency spectrum of input seismic ground motion and the width, thickness, depth and material stiffness of the lenticle are considered in this paper. Furthermore, the effect of the lenticle is investigated in layered site. The differences of influence rules between the single layered site and multi-layered site is illustrated by typical numerical example,and the soil layer properties is studied emphatically. It is illustrated a lenticle can significantly affect the ground motion both in homogenous site and layered site, and the amplification effect is more obvious in layered site. The seismic response of nonlinear site involving a lenticle is calculated by an equivalent linear method considering the effects of the lenticle. This study is emphasized on the influence rule of the nonlinear properties of soil and the frequency spectrum of input seismic waves by comparing the seismic response between corresponding analyses models. Further more, the seismic response of nonlinear layered site is modeled and computed, to mainly study the influence rules of the properties of soil layer and the amplititude and frequency spectrum of input seismic waves. It is shown that the amplification effect is significant both in layered site and homogenous site. The nonlinearity behavior of site not only decreases the peak of seismic ground motion, but also prolongs the prominent period. The amplification effect is more significant in layered site, which is similar to the case of linear site.更多还原