单一地裂缝成层地层水平地震响应分析解析解研究
发布时间：2018-08-12 13:57
【摘要】：水平成层场地地震响应的数值算法随着计算机技术的进步得到了空前的发展,但解析算法的发展却十分缓慢,且只能在某些模型足够简单,条件足够理想的情况下适用,特别是地裂缝场地条件下的解析算法更是十分少见。本文在现存地裂缝理论的研究基础之上,结合弹性波动理论,归纳出一种地裂缝场地地震响应的解析解算法,通过计算对比分析,结果表明:1、用剪切梁法和集中质量法求解水平成层场地条件下的地震响应,与有限元法计算结果相近,土层对地震波有放大效应,且计算结果受分层数、软弱土层和阻尼比等因素的影响。2、正弦简谐波输入下,透过单层和多层覆盖无裂缝场地的地震波在地表响应量均得到了放大,且对于低频入射波地震反应量增大更为明显,输入正弦波的频率接近土层的基频时地震响应量最大;与文献解相近,证明了本文提出的波动解析法的合理性。3、基于本文的波动解析法,在正弦简谐波输入下,透过单一地裂缝场地的地震波在地表处的地震响应同样得到了放大,且放大效应较非地裂缝场地更为显著,对低频波的放大效应同样高于高频波;因地裂缝上下盘的物理力学性质存在明显差异,致使上盘的放大效应大于下盘,地裂缝上下盘的放大效应均随着与裂缝距离的增大而逐渐减小。
[Abstract]:With the development of computer technology, the numerical algorithm for seismic response of horizontally stratified sites has been developed unprecedentedly, but the development of analytical algorithm is very slow, and it can only be applied in some cases where the model is simple enough and the conditions are ideal enough, especially in the case of ground fissures. Based on the study of fracture theory and elastic wave theory, an analytical solution algorithm for seismic response of ground fissure site is proposed. The results show that: 1. The shear beam method and the lumped mass method are used to solve the seismic response of horizontally stratified site, which are similar to the results of finite element method. The magnification effect is affected by the number of layers, the soft soil layer and the damping ratio. 2. Under the sinusoidal harmonic input, the seismic response of the crack-free site covered by single layer and multi-layers is amplified, especially for the low-frequency incident wave. The frequency of the input sinusoidal wave is close to the soil layer. The results show that the wave analysis method proposed in this paper is reasonable. 3. Based on the wave analysis method proposed in this paper, the seismic response at the surface of a single ground fissure site is also amplified by sinusoidal harmonic input, and the amplification effect is more significant than that at a non-ground fissure site. The amplification effect of low-frequency wave is also higher than that of high-frequency wave, and the amplification effect of upper wall is larger than that of lower wall because of the obvious difference of physical and mechanical properties between upper wall and lower wall of ground fissure.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435;P315
本文编号：2179268
[Abstract]:With the development of computer technology, the numerical algorithm for seismic response of horizontally stratified sites has been developed unprecedentedly, but the development of analytical algorithm is very slow, and it can only be applied in some cases where the model is simple enough and the conditions are ideal enough, especially in the case of ground fissures. Based on the study of fracture theory and elastic wave theory, an analytical solution algorithm for seismic response of ground fissure site is proposed. The results show that: 1. The shear beam method and the lumped mass method are used to solve the seismic response of horizontally stratified site, which are similar to the results of finite element method. The magnification effect is affected by the number of layers, the soft soil layer and the damping ratio. 2. Under the sinusoidal harmonic input, the seismic response of the crack-free site covered by single layer and multi-layers is amplified, especially for the low-frequency incident wave. The frequency of the input sinusoidal wave is close to the soil layer. The results show that the wave analysis method proposed in this paper is reasonable. 3. Based on the wave analysis method proposed in this paper, the seismic response at the surface of a single ground fissure site is also amplified by sinusoidal harmonic input, and the amplification effect is more significant than that at a non-ground fissure site. The amplification effect of low-frequency wave is also higher than that of high-frequency wave, and the amplification effect of upper wall is larger than that of lower wall because of the obvious difference of physical and mechanical properties between upper wall and lower wall of ground fissure.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435;P315
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