基岩地形对地震动影响研究

发布时间：2018-02-13 06:08

本文关键词： 基岩地形地震动谱元法数值模拟　出处：《岩土工程学报》2017年03期 　论文类型：期刊论文

【摘要】：在理论分析基础上,采用谱元法研究了基岩地形变化对地震动的影响。结果表明:1基岩面上地震动强度大小与基岩面的产状、地震波入射方向等因素相关。地震波入射方向越接近基岩面切线方向,基岩面上地震动强度越小;越接近基岩面法线方向,则越大。2基岩凸起地形的存在,导致与凸起区相对应地表处的地震动强度减弱,形成地震动强度相对减弱区;基岩凹陷地形的存在,导致与凹陷区域相对应地表处的地震动强度增强,形成地震动强度相对增强区。3基岩地形陡度不同,地震动强度相对变化区不同。基岩凸起地形作用下,地震动强度相对减弱区是基岩凸起区的1.13~1.69倍,具有随陡度增大而逐渐增大的趋势;基岩凹陷地形作用下,地震动强度相对增强区是基岩凹陷区的0.5~1倍,具有随陡度增大而逐渐减小的趋势。4覆盖层厚度不同,地震动强度相对变化区也不同。基岩凸起地形作用下,地震动强度相对减弱区与基岩凸起区的比值具有随覆盖层厚度增大而逐渐增大的趋势;基岩凹陷地形作用下,地震动强度相对增强区与基岩凹陷区的比值具有随覆盖层厚度增大而逐渐减小的趋势。
[Abstract]:On the basis of theoretical analysis, the effect of bedrock topographic variation on ground motion is studied by means of spectral element method. The results show that the magnitude of ground motion intensity and the occurrence of bedrock surface on the bedrock surface of 1: 1 are studied. The direction of incident seismic wave is related to other factors. The closer the direction of incident seismic wave is to the tangent direction of the bedrock surface, the smaller the intensity of ground motion on the bedrock surface is, and the larger the occurrence of the topography of the bedrock uplift is, the closer it is to the normal direction of the bedrock surface. As a result, the intensity of ground motion at the surface corresponding to the uplift is weakened, and the intensity of the ground motion is relatively weakened; the existence of topography of the bedrock sag leads to the increase of the intensity of the ground motion corresponding to the region of the depression. The intensity of ground motion in the area of relative enhancement of ground motion intensity is 1.13 ~ 1.69 times higher than that in the area of bedrock uplift, and the relative variation of ground motion intensity is different in the area of relative enhancement of ground motion intensity, and the relative variation area of ground motion intensity is different in the area of relative enhancement of ground motion intensity. Under the action of topography, the intensity of ground motion in the area of relative enhancement of ground motion is 0.5 ~ 1 times of that in the area of bedrock sag, and the thickness of overburden decreases gradually with the increase of steepness, and the thickness of overburden decreases gradually with the increase of steepness. The relative variation of ground motion intensity is also different. Under the action of bedrock uplift topography, the ratio of ground motion intensity relative weakening area to bedrock uplift area has the tendency of increasing with the thickness of overburden, and under the action of bedrock depression topography, the ratio of ground motion intensity relative weakening area to bedrock uplift area increases with the thickness of overburden. The ratio of the intensity of ground motion to the area of bedrock sag decreases with the increase of the thickness of the overburden.
【作者单位】：防灾科技学院;
【基金】：中国地震局教师科研基金项目(20150106) 中央高校基本科研业务费专项资金项目(ZY20160101)
【分类号】：TU45

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