共查询到16条相似文献，搜索用时 125 毫秒
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利用波函数的Fourier-Bessel级数展开法,推导了具有不同深宽比的圆弧状凹陷地形对入射平面SV波二维散射问题的解析解。区别于现有其他解析解,利用柱函数的渐近性质,使得散射波的待定系数得以直接确定,避免了线性方程组的求解以及相应的高频波入射下的数值计算问题,从而拓展了解析解适用的频带范围。通过与已有解析解的比较论证了该解析解的正确性,并在一个较宽的频带范围内研究了圆弧状凹陷地形对入射平面SV波的散射效应。 相似文献
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圆弧状凹陷地形对平面P波的散射:高频解答 总被引：2，自引：1，他引：1
利用波函数的Fourier-Bessel级数展开,推导了具有不同深宽比的圆弧状凹陷地形对入射平面P波二维散射问题的解析解.与现有解析解不同之处在于,为了使该解析解适用于更高的入射波频率,本文利用了柱函数的渐进性质,使得散射波的待定系数可以直接确定,避免了线性方程组的求解以及相关的数值计算问题,从而拓展了该解析解适用的频带范围.通过与现有解析解的比较,论证了该解析解的正确性,进而在一个较宽的频带范围内分析了圆弧状凹陷地形对入射平面P波的散射效应. 相似文献
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利用Fourier Bessel级数展开法，给出了表面具有覆盖层的圆弧形凹陷地形对入射平面SV波散射问题的一个解析解，并利用该解分析了不同深宽比凹陷地形表面覆盖层刚度和厚度对入射SV波的影响．结果表明，凹陷地形表面覆盖层的存在，即使厚度很薄，也会显著增加对入射SV波的放大作用，该放大作用可达到单一凹陷地形的2.5倍以上．覆盖层刚度和厚度的变化对入射平面SV波也具有很大影响． 相似文献
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局部地形条件对地震动放大有显著影响,解析法和数值法均可研究该问题,而解析法可以分析问题的物理本质和检验数值法的精度.将局部地形分为无盖层凹陷地形、有盖层凹陷地形(沉积谷地)、凸起地形和复合地形;分别综述了国内外关于各种局部地形对地震动影响的解析解研究成果.从以下4个方面分析和讨论当前研究成果:①研究方法;②计算介质模型;③各局部地形研究水平的不均衡;④研究存在不足之处.提出了未来发展方向:未来该领域应加强研究局部地形对Rayleigh波地震动响应规律,开展局部地形对多种波耦合入射下的地震动响应规律的研究,运用非线性波动理论研究局部地形对地震动的影响和开展三维非线性地震动数值模拟研究. 相似文献
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平面SH波在相邻多个半圆形凹陷地形上的散射 总被引：13，自引：0，他引：13
本文利用复变函数和多极坐标方法研究平面SH波对相邻多个半圆形凹陷地形的散射问题。文中首先给出了相邻多个半圆形凹陷地形对SH波散射的波函数,进一步利用移动坐标的方法逐一地满足凹陷地形的边界条件。最后将解的问题归结为对一组无穷代数方程组的求解。作为算例,对具有两个半圆形凹陷地形的问题进行了分析,给出了数值结果,并进行了一些讨论。 相似文献
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Rayleigh波在浅圆凹陷地形附近的散射:高频解答 总被引：4，自引：1，他引：4
利用波函数展开法给出了Rayleigh波在浅圆凹陷地形附近散射的一个高频解析解，并分析了入射频率、凹陷地形宽度和深度等因素对波散射的影响。数值结果表明，由于Rayleigh波幅值随深度而衰减，凹陷地形表面位移幅值整体上较小，且随着凹陷地形深度的增加而减小；由于Rayleigh波幅值还随频率而衰减，随着入射频率的升高，凹陷地形表面位移幅值逐渐减小；由于凹陷地形的屏障作用，在人射波的近端，地表位移分布变得相对复杂，地表位移峰值出现在左角点附近，而在入射波远端，地表位移分布相对简单，地表位移峰值出现在距凹陷地形较远的地方。 相似文献
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阶跃SH波作用下半圆形凹陷地形的瞬态反应—长期解 总被引：1，自引：0，他引：1
本文利用Ｌａｐｌａｃｅ变换和波函数展开方法讨论了在阶跃的ＳＨ位移波作用下半圆形凹陷地形的瞬态反应问题。经Ｌａｐｌａｃｅ反演后，求出了阶跃ＳＨ波通过凹陷地形后散射位移场的长期解。最后给出了在不同时刻凹陷地形表面上各点的位移反应。 相似文献
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曲线坐标在弹性波散射研究中的应用──SH波对不等深度凹陷地形的散射 总被引：1，自引：0，他引：1
本文利用曲线坐标的分析方法研究ＳＨ波对凹陷地形散射的边值问题。首先给出了在曲线坐标系中波动方程解的逼近函数序列，并使此解满足由曲线坐标所描述的具有不同深度的凹陷地形上的边界条件，最后将待解的问题归结为对一组无穷代数方程组的求解．本文提供的方法有如下的特点：（１）可将通常求解凹陷地形对ＳＨ波散射的波动方程的混合边值问题（指在不同边界区域上给出不同的应力分量的边界条件）化为一应力边值问题；（２）本文所使用的曲线坐标，可描述具有不同深度与宽度比的拟半圆形凹陷地形散射问题，并给出一般解；（３）本文方法可推广用于求解Ｐ（－ＳＶ）波对凹陷地形的散射问题。作为算例，本文给出了ＳＨ波对具有不同深度与宽度比的凹陷地形散射的数值结果，并进行了分析比较。 相似文献
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Yushan Zhang 《地震科学（英文版）》2010,23(2):157-165
By expressing the wave functions in the form of Fourier-Bessel series,the analytical solution for the two-dimension scattering problem of plane P waves by the cylindrical canyon topography that contains arbitrary number of circular-arc-shaped layers is presented firstly.And then,the convergence of the proposed series solution with the truncation number of terms is discussed,which demonstrates that the analytical solution can converge even for very high frequencies of the incident P wave.Finally,using this solution,the influences that are imposed on the stationary ground motion by the number and the sequence of alluvial layers,as well as the stiffness of soft interlayer contained in the canyon,are studied. 相似文献
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Yang Caihong 《中国地震研究》2010,24(2):155-166
Through the Fourier-Bessel series expansion of wave functions,the analytical solution to the two-dimensional scattering problem of incidental plane P waves by circular-arc canyon topography with different depth-to-width ratio is deduced.Unlike other existing analytical solutions,in order to ensure that the analytical solution is valid for higher frequency incident waves,the asymptotic properties of cylindrical functions are in this paper introduced to directly determine the unknown coefficients of scattering waves,avoiding the solution of linear equation systems and corresponding numerical issues,which in turn expand the frequency band in which the analytical solution is valid.Comparison with other existing analytical solutions demonstrates that the proposed analytical solution is correct.Furthermore,the scattering effects of a circular-arc canyon on the incident plane P wave are analyzed in a comparatively broad frequency band. 相似文献
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Introduction The effect of local topographies on seismic wave propagation is one of the most attractive topics in seismology. It may be resolved by either an analytical method or a numerical method. Here, the analytical method is the wave function expansion method; numerical methods include the finite difference, finite element, boundary integration equation, and discrete wave number method, etc. The advantage of these numerical methods is that they can be applied to local inhomogeneity and ir… 相似文献
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Diffraction of plane SV waves by a shallow circular-arc canyon in a saturated poroelastic half-space 总被引：7，自引：0，他引：7
Jianwen Liang Zhenning Ba Vincent W. Lee 《Soil Dynamics and Earthquake Engineering》2006,26(6-7):582-610
An analytical solution for the scattering and diffraction of incident plane SV waves by a shallow circular-arc canyon in a saturated poroelastic half-space is derived by the wave function expansion method. The solution is utilized to analyze the dependence of the computed surface motions on the incident frequencies, incident angles, porosity, boundary drainage and Poisson's ratio. It is shown that, depending on the incident angles, the surface displacement amplitudes around a canyon in a dry poroelastic half-space and saturated poroelastic half-space can be very different. The surface displacement amplitudes of an undrained saturated poroelastic half-space are close to those of a drained saturated poroelastic half-space. For low porosity, the surface displacement amplitudes of a saturated poroelastic half-space are almost identical to those of a dry poroelastic half-space, and drainage condition has little influence on the surface displacement amplitudes. But for high porosity, the effect of drainage condition becomes significant, and for the same porosity, the displacement amplitudes of an undrained saturated half-space will be larger than those of a drained saturated half-space. Poisson's ratio is also an important factor affecting the surface displacement amplitudes around the canyon, both in drained and undrained conditions, but leads to larger effects for an undrained saturated half-space than for a drained saturated half-space. Large pore pressures are found around the canyon and their amplitudes depend on the incident angles and frequencies. Below the surface, the amplitudes of pore pressures are less than they are at the surface, especially for high frequencies. 相似文献
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