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对瑞利面波的研究过去主要注重其速度频散信息,而对其位移特征研究相对较少一些。本文主要研究水平层状介质模型的瑞利波单点谱比曲线计算,同时对曲线特征进行分析。采用水平层状介质模型,应用传递矩阵方法推导地表瑞利面波的质点位移表达式。对于工程中常见的3种典型层状介质模型,利用频散方程和波数加权平均的方法求各模型的瑞利波频散曲线以及合并化的速度频散曲线,再进一步利用地表质点位移计算公式和位移权值法分别计算各模式的H/V谱比曲线以及所有模式的合并化H/V谱比曲线。由此可见,本文在研究H/V谱比曲线时考虑了瑞利波多模式同时存在的问题。由模拟计算结果可知:对于规则地层模型和含硬夹层的地层模型而言,合并化的H/V谱比曲线与基阶模式H/V谱比曲线基本吻合;而对含有软夹层的复杂地层模型来说,基阶模式H/V谱比曲线与合并化的H/V谱比曲线之间存在十分明显的差异。由此说明在某些情况下基阶模式H/V谱比曲线不能代表整个地层的响应。
In the past, the research on Rayleigh surface waves mainly focused on its velocity dispersion information, but relatively few studies on its displacement characteristics. In this paper, we mainly study the Rayleigh single-point spectral ratio curve calculation of horizontal layered medium model, and analyze the curve characteristics at the same time. Using horizontal layered media model, the transfer matrix method is used to derive the particle displacement expression of surface Rayleigh wave. For the three typical layered media models commonly used in engineering, the Rayleigh wave dispersion curves and the combined velocity dispersion curves of each model are obtained by using the dispersion equation and wavenumber weighted average method, and then the formula of surface mass point displacement is further utilized And displacement weight method were calculated for each mode H / V spectral ratio curve and the combined H / V spectral ratio curve for all modes. Thus, this paper considers the simultaneous existence of multiple modes of Rayleigh waves while studying the H / V spectral ratio curve. From the results of simulation, it can be seen that the H / V ratio curve of the merged H / V spectrum is basically in agreement with the H / V ratio curve of the regular formation model and the formation model with hard interlayer, while the complex formation with soft interlayer Model, there is a very significant difference between the H / V spectral ratio curve and the combined H / V spectral ratio curve of the base mode. This shows that in some cases, the fundamental mode H / V spectral ratio curve can not represent the response of the entire formation.