地层结构对地表地震响应的影响研究

Influence of Stratigraphy on Surface Seismic Response

以软土地区常见的淤泥质粘土、粉质粘土、粉质粘土夹粉砂三种土性地层概化组成不同地层结构,利用频谱特性差异较大的El-Centro及Concrete地震波,模拟分析地层结构对地表地震响应的影响。获得的地面各类动力响应(加速度时程与峰值、速度时程与峰值、位移时程与峰值、位移残余值、Fourier谱、能量谱、反应谱等)表明,两种地震波作用下地表的地震响应规律性相似,说明地震作用下地层结构的影响具有普遍性;不同的地层结构,地表的地震响应存在差异;从上往下,土层弹性模量依次为高-低-中及中-低-高的地层组合结构的抗震效果较好。场地地震效应影响分析,应将地层结构特性作为地质条件的重要内容予以充分重视。

The common three kinds of earthiness formations （muddy silt clay, silty clay and silty clay clamp silt） in soft soil area, generalized formation the different strata structure, and simulation analysis the formation structure on the influence of surface seismic response by using the spectrum characteristic differences of EI-Centro and Concrete seismic wave. Above ground, various forms of dynamic response （acceleration history and peak, speed range and peak, shift schedule and peak, displacement residual value, Fourier spectrum, energy spectrum, response spectrum, etc.） show that the surface seismic response caused by two types of seismic wave is similar, and indicate that the influence of structural formations is universal during earthquakes, so that different stratigraphic configurations create the differences in surface seismic response. From up to down, the seismic effect is good when the soil modulus of elasticity is ordinal in high-low-middle and middle-low-high of stratum composite structure. Analysis of seismic effects at a particular site should pay close attention to the stratigraphic structure and characteristics, as they are a fundamental control on the geological conditions.