【摘要】 针对地基土卓越周期与结构物自振周期接近而产生共振破坏以及地震中的许多震害均与地基土的卓越周期密切相关的情况,以场地土为研究对象,设计了不同试验方案,通过室内波速试验,分别模拟不同密度、含水量以及应力状态下粘土、砂土和粉土的剪切波响应特性,分析了场地土卓越周期变异的规律。试验结果表明,在建设荷载等各种因素的作用下,地基土密度加大,弹性模量提高,从而改变了土体的动力性质,地震波传播的速度变快,地层的卓越周期减小,局部或整体地改变场地类别,从而影响到原有建筑物的抗震设计。在抗震设计中应综合考虑建筑前后场地类别随地基土卓越周期变化对建筑物的抗震影响。更多还原

【Abstract】 The resonance damage between superstructure and subsurface soil will occur when site soil predominant period and structure natural period approaches,and many earthquake disasters are closely related to the predominant period of site soil in earthquake.Through a large number of wave velocity experiments,with different testing programs designed,the shear wave velocities of clay,sandy soil and silty soil in different density,water content and stress condition were respectively simulated to analyze the site soil predominant period variation.The laboratory test results indicated that,under the function of different factors,the site soil density was strengthened,and elastic modulus was enhanced.Therefore,dynamic characteristics of site soil were changed,and the transmission of earthquake wave became faster,which leads to decreases of the site soil predominant period.Accordingly,the classification of the site was changed partially or entirely,and the anti-earthquake design of previous buildings would be influenced.The soil was denser,and the consumption of the seismic wave transmitting among soil-layers was less.Then,the vibration region influenced more widely,and the area where the earthquake involves was expanded.Therefore,onward variation of site soil predominant period and impact of site type variation on anti-earthquake factor should be considered in anti-earthquake design.更多还原