地铁地下结构非线性地震响应分析

地铁地下结构非线性地震响应分析(任务书,开题报告,论文12000字)
摘  要
目前在对地下结构进行地震响应分析时，一般将土体视为线弹性材料，而计算模型变得越来越复杂，必须借助于成熟的商业计算软件，但成熟商业软件中缺乏合适的土体非线性模型。本文基于ANSYS软件自带的APDL语言，编写了基于等价非线性化方法的程序，以考虑土体非线性特性，并将计算结果与考虑土体线性时的结果进行比较，研究土体非线性特性对地下结构及周围场地土地震响应的影响。
本文首先依据等价非线性基本理论，以土体的动模量函数和阻尼比函数为基础，编写了等价非线性程序，通过与较成熟的商业软件ERRA进行对比，证明了程序的正确性。然后利用编制的程序对典型地铁车站结构进行了线性和非线性的计算，研究结果表明：（1）由于土体的非线性变形耗散一定的地震能量，结构在线性时的响应显著大于非线性的；（2）由于土体非线性时模量衰减，其刚度降低，因而非线性时基频降低；（3）由于土体的滤波效应，相对于线性时，非线性时中高频成分相对较少；（4）考虑土体非线性时，地下结构会减小周围场地土的动力反应。
由此可见，土体非线性特性对地下结构地震响应影响显著，因而，在实际地下结构的抗震计算分析中，应考虑土体的非线性特性。本文开发的等价非线性程序对完善地下结构非线性地震响应计算方法具有一定的价值意义。
关键词：地下结构；地震响应；土体非线性；等价非线性方法

Abstract
At present, when the seismic response of the underground structure is analyzed, the soil is generally regarded as a linear elastic material, and the calculation model becomes more and more complicated. It is necessary to use mature commercial computing software, but the mature commercial software lacks suitable soil non-linear model. Based on the APDL language of ANSYS software, this paper has written a program based on the equivalent nonlinear method to consider the nonlinear characteristics of soil and compare the calculated results with the results when the soil is linear in order to study the influence of soil nonlinear characteristics on earthquake response of underground structures and surrounding soil.
Based on the equivalent nonlinear basic theory, and the dynamic modulus function and damping ratio function of the soil, an equivalent nonlinear program is written and compared with the mature commercial software ERRA. The correctness of the program has been proved . Then the linear and non-linear calculation of the typical subway station structure is carried out by using the developed program. The results show that: (1) Because the nonlinear deformation of the soil dissipates a certain amount of seismic energy, the response of the structure in the linearity is significantly larger than that of the nonlinear;(2) Due to the non-linear modulus attenuation of the soil, the stiffness decreases and the non-linear time-frequency decreases;(3) Due to the soil filter effect, relative to the linear, non-linear high-frequency components are smaller; (4) Considering the nonlinearity of the soil, the underground structure will reduce the dynamic response of the surrounding soil.
It can be seen that the nonlinear characteristics of the soil have a significant effect on the seismic response of the underground structure. Therefore, the nonlinear characteristics of the soil should be taken into account in the seismic analysis of the actual underground structure. The equivalent nonlinear program developed in this paper has certain value to perfect the nonlinear seismic response calculation method of underground structure.
Key words: Underground structure; Seismic response; Soil nonlinearity; Equivalent nonlinear method
 
目  录
第1章 绪论    2
1.1 引言    2
1.2 国内外研究现状    2
1.3研究内容    4
第2章 等效非线性计算基本理论    6
2.1 土的动本构关系    6
2.2 等效非线性模型    7
2.2.1动模量函数    7
2.2.2 阻尼比函数    8
2.3 小结    9
第3章 等价非线性程序编写及验证    10
3.1程序编写流程图    10
3.2 程序验证    11
第4章 典型地铁车站结构非线性地震响应分析    13
4.1 计算模型及参数    13
4.2 计算工况    14
4.3 计算结果及分析    15
4.3.1土体地震响应分析    15
4.3.2 车站结构加速度响应分析    16
4.3.3车站结构变形分析    18
4.3.4 地下结构对周围场地土地震响应的影响    19
第5章 结论与展望    21
参考文献    22
致谢    24