考虑地震波幅值衰减的斜入射二维自由场

何卫平,何蕴龙

振动与冲击 ›› 2016, Vol. 35 ›› Issue (1) : 83-88.

PDF(1793 KB)
PDF(1793 KB)
振动与冲击 ›› 2016, Vol. 35 ›› Issue (1) : 83-88.
论文

考虑地震波幅值衰减的斜入射二维自由场

  • 何卫平,何蕴龙
作者信息 +

Free Field Motions Considering Amplitude Attenuation of Oblique Incident Seismic waves

  • HE Wei-ping, HE Yun-long
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文章历史 +

摘要

本文将传统基于地震波垂直入射的自由场构建方案推广到地震波斜入射情况。在假设平面半空间自由场由以特定角度组合入射的平面P波、SV波及其反射波构成的前提下,通过引入介质品质因子、临界幅值比和子波影响距离等参数完成了均匀线弹性介质中基于地表地震记录、考虑地震波衰减影响的自由场构建。通过地基特征点处入射P波、SV波的时、频域特性,特征点位移时程研究了临界幅值比和地震波幅值衰减因素对自由场的影响。结果显示,对于水工结构等低频激励起主要影响的结构来说,构建自由场时临界幅值比的选择具有较大自由性;在岩体较完整、涉及范围较小时,地震波幅值衰减因素对自由场的影响较小,可忽略不计;但在一些极端情况下,地震波幅值衰减因素对自由场的影响可能达到20%左右。

Abstract

The traditionally used scheme of free field motions based on vertical incident seismic waves is expanded to the condition of oblique incident seismic waves in this paper. The assumption that free field motions in half plane space is contributed by oblique incident P and SV waves with arbitrary angles and their reflected waves is made firstly. Secondly the parameters of seismic quality factor, critical amplitude ratio and the influence distance of single wave are introduced to accomplish the model. Finally the free field motions based on surface earthquake records and considering the amplitude attenuation of seismic wave are obtained. The influence of critical amplitude ratio and seismic quality factor on the frequency characteristic and motions of specified point in half plane space is discussed. The result shows that a wide range of critical amplitude ratio is acceptable for the structure with low natural frequency such as hydraulic dams in the construction of free field motions. And in the condition of high quality rock mass and small spatial range, the amplitude attenuation effect could be ignored in the construction of free field motions. While in some extreme cases, the amplitude attenuation effect would change the free field motions in about 20 percent.

关键词

自由场 / 斜入射 / 幅值衰减 / 品质因子 / 临界幅值比 / 子波影响距离

Key words

Free field motions / Oblique incident / Amplitude attenuation / Seismic quality factor / Critical amplitude ratio / influence distance of single wave

引用本文

导出引用
何卫平,何蕴龙. 考虑地震波幅值衰减的斜入射二维自由场[J]. 振动与冲击, 2016, 35(1): 83-88
HE Wei-ping, HE Yun-long. Free Field Motions Considering Amplitude Attenuation of Oblique Incident Seismic waves[J]. Journal of Vibration and Shock, 2016, 35(1): 83-88

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