刘中宪, 武凤娇, 王冬. 沉积盆地-山体耦合场地对平面P波、SV波和Rayleigh波的二维散射分析[J]. 工程力学, 2016, 33(2): 160-171. DOI: 10.6052/j.issn.1000-4750.2014.05.0396
引用本文: 刘中宪, 武凤娇, 王冬. 沉积盆地-山体耦合场地对平面P波、SV波和Rayleigh波的二维散射分析[J]. 工程力学, 2016, 33(2): 160-171. DOI: 10.6052/j.issn.1000-4750.2014.05.0396
LIU Zhong-xian, WU Feng-jiao, WANG Dong. TWO DIMENSIONAL SCATTERING ANALYSIS OF PLANE P, SV, AND RAYLEIGH WAVES BY COUPLED ALLUVIAL BASIN-MOUNTAIN TERRAIN[J]. Engineering Mechanics, 2016, 33(2): 160-171. DOI: 10.6052/j.issn.1000-4750.2014.05.0396
Citation: LIU Zhong-xian, WU Feng-jiao, WANG Dong. TWO DIMENSIONAL SCATTERING ANALYSIS OF PLANE P, SV, AND RAYLEIGH WAVES BY COUPLED ALLUVIAL BASIN-MOUNTAIN TERRAIN[J]. Engineering Mechanics, 2016, 33(2): 160-171. DOI: 10.6052/j.issn.1000-4750.2014.05.0396

沉积盆地-山体耦合场地对平面P波、SV波和Rayleigh波的二维散射分析

TWO DIMENSIONAL SCATTERING ANALYSIS OF PLANE P, SV, AND RAYLEIGH WAVES BY COUPLED ALLUVIAL BASIN-MOUNTAIN TERRAIN

  • 摘要: 盆山耦合地形作为一种常见的复杂场地,其对地震动的复合影响目前尚未得到清晰认知。为此,引进一种高精度的有限元-间接边界积分方程耦合方法(FEM-IBIEM),探讨沉积盆地及其邻近山体对地震波(平面P波、SV波和Rayleigh波)的多次散射作用。数值结果表明:沉积盆地及其邻近山体存在显著的动力相互作用,整体位移响应特征依赖于山体、盆地的空间位置和几何特征,入射地震波的频率和角度等因素;整体上看,P波垂直入射下,较高山体的存在对沉积盆地内部位移具有明显的放大效应;SV波入射下,山体的影响相对较小,且盆地内部不同位置可能会表现出完全不同的放大或缩小特征;Rayleigh波从山体一侧入射时,山体对沉积盆地存在明显的"屏障"作用,而从盆地一侧入射时,在低频段山体反而会表现出放大作用;总体上看较高山体对沉积盆地的影响程度更为显著。鉴于山体的存在显著改变了沉积盆地的位移幅值和频谱特性,实际盆地的地震动确定需考虑邻近山体的影响。

     

    Abstract: Coupled basin-mountain terrain is a common complex site, but the combined effect of such sites on ground motion is currently not clear. Therefore, the scattering of seismic waves (plane P, SV and Rayleigh waves) by coupled basin-mountain terrain is investigated by an accurate finite element-indirect boundary integral equation method (FEM-IBIEM) coupled method. Through detailed numerical analysis, it is shown that there exists significant dynamic interaction between the basin and its neighboring mountain, and the total response characteristics mainly depend on the effects of spatial location and geometric characteristics of the mountain, the frequency and angle of the incident waves, etc. Overall, for the vertical incidence of P waves, the mountain has significant amplification effects on the displacement amplitude in the basin. For the incidence of SV waves, the effects of the mountain on the nearby basin are smaller and different locations within the basin may exhibit completely different amplification or de-amplification features. For the incidence of Rayleigh waves coming from the mountain's side, the mountain mainly has a shielding effect on the basin. Meanwhile, for the incidence of waves coming from the basin's side, the mountain may have a notable amplification effect on the basin for low frequency waves. In general, the influence of nearby high mountains on the alluvial basin seems greater. In consideration of the significant effect of the mountain on the amplitude and frequency characteristics of the dynamic response in the basin, the actual simulation of ground motion in basin needs to consider the impacts of the adjacent mountain.

     

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