基于FLAC3D的液化土层地震反应研究

发布时间：2018-06-10 05:40

本文选题：FLAC + 液化　；参考：《中国地震局工程力学研究所》2016年硕士论文

【摘要】：自1964年日本新泻地震以来,地震液化问题已引起岩土工程界的广泛关注。近年来的几次大地震中,液化引起的结构不均匀沉降依然是地震灾害的重要形式之一,如2011年东日本大地震、2011年新西兰基督城地震和2016年的台湾高雄地震。对于地震液化的研究虽然已取得了很大进展,但由于影响因素繁多,液化导致的结构不均匀沉降的规律及沉降量的预测仍是未来的重要研究方向。数值模拟是研究液化的重要手段。FLAC3D软件具有很强的解决复杂力学问题的能力,具有建模方便、参数可调和计算便捷的特点,其应用范围已经扩展到土木建筑、交通、水利、地质、环境工程等领域。利用该软件进行液化研究的成果较少,而且大部分只局限于自由场的液化模拟或液化场地桩基的地震反应分析,对于液化对结构沉降的影响研究还有待于进一步开展。本文采用FLAC3D,对可液化场地进行了大量不同工况的计算,初步研究了引起建筑物不均匀震陷的机理以及土层液化对地震动的影响。主要的工作包括:1.系统总结了建筑物不均匀震陷的研究成果以及FLAC3D软件的应用研究现状,选取了适宜的边界条件及孔压增长模型,建立了适用于液化分析的计算模型,对模型计算结果的可靠性进行了检验。2.构建了16种不同计算模型,分析了液化层埋深和厚度变化对结构不均匀沉降的影响,总结了埋深与厚度的影响规律,并给出了初步分析。3.研究了输入地震动的不同特性对结构不均匀沉降的影响,包括波序、荷载类型、幅度、不规则性以及频率等,给出了各因素对结构不均匀震陷的影响规律。4.分别多角度分析了土层液化对地震动的影响,得到了土层液化会降低地震动幅值以及高频减震低频放大的结果,计算结果与实际震害调查结果相符。
[Abstract]:Since the Niigata earthquake in 1964, earthquake liquefaction has attracted wide attention in geotechnical engineering. In recent years, structural uneven settlement caused by liquefaction is still one of the important forms of earthquake disasters, such as the East Japan earthquake in 2011, the Christchurch earthquake in New Zealand in 2011 and the Kaohsiung earthquake in Taiwan in 2016. Although great progress has been made in the study of seismic liquefaction, the law of uneven settlement and prediction of settlement caused by liquefaction are still important research directions in the future. Numerical simulation is an important means to study liquefaction. FLAC3D software has a strong ability to solve complex mechanical problems, has the characteristics of convenient modeling, convenient parameter harmonic calculation, its application scope has been extended to civil construction, traffic, water conservancy, Geology, environmental engineering, etc. The results of liquefaction research using this software are few, and most of them are confined to the liquefaction simulation of free field or the seismic response analysis of pile foundation in liquefaction site. The research on the influence of liquefaction on structural settlement needs to be further developed. In this paper, FLAC3D is used to calculate a large number of liquefiable sites under different working conditions. The mechanism of uneven seismic subsidence of buildings and the effect of soil liquefaction on ground motion are preliminarily studied. The main tasks include: 1. The research results of uneven seismic subsidence of buildings and the application status of FLAC3D software are summarized systematically. The appropriate boundary conditions and pore pressure growth model are selected, and the calculation model suitable for liquefaction analysis is established. The reliability of the model calculation results is tested. 2. 2. In this paper, 16 different calculation models are constructed, and the influence of buried depth and thickness of liquefaction layer on uneven settlement of structure is analyzed. The influence law of buried depth and thickness is summarized, and a preliminary analysis of .3. is given. The influence of different characteristics of the input ground motion on the uneven settlement of the structure, including wave sequence, load type, amplitude, irregularity and frequency, is studied. The effects of soil liquefaction on ground motion are analyzed from different angles. The results of reducing the amplitude of ground motion and the low frequency amplification of high frequency earthquake absorption are obtained. The calculated results are in agreement with the actual results of earthquake damage investigation.
【学位授予单位】：中国地震局工程力学研究所
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU435

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