【摘要】 地表土层通常具有成层的特点,在地震工程中将覆盖土层简化为力学性质沿竖向成层变化,水平向为各向同性的层状半空间体才会得到更符合实际情况的解答。采用频域分析方法,对多层横观各向同性土层对垂直向上的入射剪切波的反应进行了分析。在此基础上,分析了自由场地面运动的频率响应函数,计算了响应位移的功率谱密度函数,并给出了算例。算例表明,多层土的功率谱密度函数具有多个峰值。采用频域分析方法计算层状土地基在地震作用下的位移和应力响应,避免了时域分析时对波在界面处多次反射和透射的反复追踪,思路清晰,步骤简明。更多还原

【Abstract】 The ground soils are usually layered,and in earthquake engineering,it is reasonable to assume that the mechanical properties of the ground soils vary with the depth of soil,and are homogeneous in all horizontal layers.The analysis method in frequency domain is adopted to treat the transversely isotropic multi-layered soils,and response of soil layers under the upward shear waves is obtained.Based on the above analysis,the frequency response function of free-field ground motion is established.The power spectrum density function of displacement is calculated.An example is also given to illustrate the variation of the power spectrum density function via frequency,it is shown that the power spectrum density function of multi-layered soil has more peaks.Furthermore,by adopting the frequency domain analysis method,the calculation for stress and displacement responses of the layered foundation under earthquakes will be much more simplified due to avoiding the multiple tracing to the reflections and transmissions of the waves on the soil interface in time domain analysis.更多还原