摘要
采用有限元方法计算了SV波入射下相邻2个半圆凸起地形的地震响应。以地震波从左侧入射的单个凸起地形的响应作为参照,比较分析了相邻半圆凸起间的相互影响,研究结果表明:左侧半圆凸起对右侧半圆凸起的影响,比右侧半圆凸起对左侧半圆凸起的影响大;左侧半圆凸起使右侧半圆凸起地表的时程峰值变小,而右侧半圆凸起对左侧半圆凸起表面的时程峰值影响不大;不同入射角度、不同入射波频率和不同的凸起间距对谱放大系数β产生的影响有差异,但有一个非常明显的现象,即存在一个临界频率η_(cr)(本文等于1.0)。当η<η_(cr)时,入射波频率、入射角度和凸起间距影响很大,但无规律可循;当η>η_(cr)时,对于相同的入射角度和入射频率,不同的凸起间距的谱放大系数β的差别很小,且随着η的增大,凸起间距对谱放大系数β的影响越小。这一临界频率η_(cr)与土介质剪切波速C_(S)和凸起地形的宽度2 a相关,因此,当输入波波长大于凸起地形的宽度时,相邻凸起的影响可以忽略。
In this paper,the seismic response of two adjacent semi-cylindrical hills for incident SV wave is calculated by finite element method.Taking the response of a single hill incident with the seismic wave incident from the left as a reference,the interaction between adjacent hills is compared and analyzed,and the following conclusions are obtained.The influence of the left hill on the right hill is greater than that of the right hill on the left hill.The left hill has a great influence on the time history peak of the right hill surface,making the peak smaller,while the right hill has little influence on the peak of the left hill surface.Different incident angles,different incident wave frequencies and different hill distance have different effects on the spectral amplification coefficientβ,but a very obvious phenomenon could be found,that is,there is a critical frequencyη_(cr)(equal 1.0 in this paper).Wave frequencies,angles and hill distance have a very large influence on the spectral amplification coefficient whenη<η_(cr)but there is no rule to follow.When the caseη>η_(cr),there is little difference in the spectral amplification coefficientβfor the same incident angles,incident wave frequencies and different hill distance.And the influence of different hill distance on the spectral amplification coefficient β decreases with the increasing frequencyη.This critical frequencyη_(cr)is related to the shear velocity C_(S) of the soil and the width of the hill 2 a.Therefore,when the input wave wavelength is greater than the width of the hill,the influence of adjacent hill can be ignored.
作者
丁海平
张如艳
于彦彦
DING Haiping;ZHANG Ruyan;YU Yanyan(Key Laboratory of Structural Engineering of Jiangsu Province,Suzhou University of Science and Technology,Suzhou 215011,China)
出处
《自然灾害学报》
CSCD
北大核心
2023年第5期44-55,共12页
Journal of Natural Disasters
基金
国家自然科学基金项目(51808371)。
关键词
相邻凸起地形
无量纲频率
谱放大系数
动力相互影响
adjacent semi-cylindrical hills
dimensionless frequency
spectral amplification coefficient
dynamic interaction
