P波斜入射条件下陡坎地形对场地效应的研究

发布时间：2018-06-03 23:24

本文选题：陡坎地形 + 斜入射　；参考：《苏州科技学院》2015年硕士论文

【摘要】：地震时局部不规则地形对地面运动有很大的影响,地形效应一直是地震工程领域研究的热点之一,有关各类地形对地面地震动的影响研究已有很多。由于陡坎地形本身的特点,不适合采用解析方法,多以地震波垂直入射数值分析为主,对陡坎地形在地震波斜入射条件下的研究很少。本文借助软件ANSYS,采用有限元法和人工透射边界相结合的方法,探讨了P波斜入射条件下,陡坎地形对陡坎上侧(坡顶)和陡坎下侧(坡脚)的影响程度和影响范围。本文得到主要成果如下:(1)陡坎上侧(坡顶)地震动放大系数大于水平自由地表,陡坎下侧(坡脚)地震动放大系数小于水平自由地表。(2)随着坡角的变化,陡坎上侧和下侧的场地影响范围基本保持不变。若陡坎左侧低右侧高,则入射波从陡坎左侧斜入射时,对陡坎上侧的影响范围要比从陡坎右侧入射时的大;而对陡坎下侧的影响范围则相反。(3)入射波从左侧入射时,陡坎上侧场地影响范围随着入射角度的变大而增大;入射波从右侧入射时,陡坎下侧场地影响范围随着入射角度的变大也增大。(4)覆盖层的存在,对陡坎两侧地表的地震动峰值都具有明显的放大作用,但对于不同部位测点的地震动峰值放大强度有所不同;随着覆盖层厚度的增加,各测点地震动放大系数逐渐变大。最后,对本文的研究工作进行了总结,指出今后有待于进一步研究的问题。
[Abstract]:Local irregular topography has great influence on ground motion during earthquakes. Topographic effect has been one of the hotspots in seismic engineering field. Many researches have been done on the effects of various topographical factors on ground motion. Because of the characteristics of steep ridge terrain, it is not suitable to adopt analytical method, and the numerical analysis of vertical incidence of seismic wave is the main method, but there is little research on steep ridge terrain under the condition of oblique incidence of seismic wave. In this paper, with the aid of software ANSYSand the finite element method and artificial transmission boundary method, the influence of steep ridge topography on the upper side (top) and the lower side (foot) of steep ridge is discussed under the condition of P-wave oblique incidence. The main results are as follows: (1) the magnification factor of the ground motion on the upper side of the steep canyon is greater than that of the horizontal free surface, and the magnification factor of the ground motion at the bottom of the steep ridge is smaller than that of the horizontal free surface. The site impact range of the upper and lower sides of the steep canisters remains basically unchanged. If the left side of the steep ridge is low and the right side is high, the range of influence on the upper side of the steep ridge is larger than that on the right side of the steep ridge when the incident wave is diagonally incident from the left side of the steep ridge, while the influence range on the lower side of the steep ridge is opposite to that on the lower side of the steep ridge when the incident wave is incident from the left side. The influence range of the site on the upper side of the steep canister increases with the increase of the incidence angle, and when the incident wave is incident from the right side, the influence area of the site on the lower side of the steep ridge increases with the increase of the incidence angle. The peak values of ground motion on both sides of steep ridge are obviously magnified, but the magnification intensity of the peak values of ground motion is different for different measuring points, and the magnification factor of ground motion increases gradually with the increase of the thickness of overburden. Finally, this paper summarizes the research work and points out the problems to be further studied in the future.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435

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