【作者】 李舒；

【导师】 邹立华； 石玉成；

【作者基本信息】 兰州交通大学 ， 防灾减灾工程及防护工程， 2011， 硕士

【摘要】 土遗址是我国不可移动文物领域的重要组成部分,在我国的西北地区赋存有许多处国家级重点保护文物。历经千百年的岁月,承受多种病害侵损的土遗址存在着不同程度的安全隐患；同时许多土遗址更是位处于强震多发地区,地震潜在危害不容忽视。因此,开展土遗址抗震稳定性分析,并对其进行安全性评价,对于土遗址的抗震防护以及防灾减灾具有重要意义。本文以甘肃省高台地区国家级重点文物保护单位——骆驼城土遗址为例,通过实地调查、现场测绘、资料查阅等方式厘清了骆驼城土遗址的工程地质与岩土工程等条件,分析了其病害特征及成因机制；通过原位动力测试、室内试验、资料查阅等手段获取了土遗址基本的物理力学参数；利用了MATLAB数值软件对计算参数进行了统计；通过数值模拟,对骆驼城土遗址分别进行了模态分析、瞬时动力学分析、伪动力可靠度、动力可靠度分析、敏感度以及参数相关性分析。以破坏阈值为判定标准,对骆驼城土遗址在地震荷载作用下的稳定性进行了评估并得出了具有显著意义的结论。本文取得的主要进展与结果具体如下：1.厘清了骆驼城土遗址所在区域范围内的气象、水文、地质、地震活动性等工程地质与岩土工程条件,分析研究了骆驼城土遗址的建筑形制、病害特征、病害成因及保护现状。2.分析研究了骆驼城土遗址构筑材料的常规物性参数和动力学参数,包括振型、自振频率、波速、弹性模量、阻尼比、泊松比、抗剪强度以及材料的极限应力等。3.基于地震动能量分布理论,利用小波算法设计了输入地震动的小波优化法,有效提高了计算效率,在保证计算精度的基础上改进了随机有限元的计算方法,并通过振型分解法对三层框架结构的计算,验证了优化计算方法的可靠性。4.计算了不同边界约束下骆驼城土遗址的模态特征,分析了不同烈度下城墙的位移场、加速度和应力场的基本分布特征与变化规律和土遗址发生破坏的可能模式及其破坏条件。5.综合分析了概率统计理论应用于土遗址抗震稳定性研究的适用性与优势,将改进的伪动力可靠度和动力可靠度方法引入土遗址抗震稳定性的分析研究中,建立了联合试验数据与计算结果对土遗址抗震稳定性进行判定的方法。6.通过计算基于一定分布特征的随机输入和输出变量的敏感性和相关性,分析研究了地震力、墙体密度、材料泊松比和墙体的相对独立长度对土遗址抗震稳定性能产生影响的程度和方式。更多还原

【Abstract】 Earthen ruins are important part of our country immovable cultural relics, there are many national key protecting of earthen ruin in the northwest of China. During thousands of years, earthen ruins, which suffered from various diseases, have different degree safety hazard. Meanwhile, lots of earthen ruins locate in strong earthquake areas and the potential danger of earthquake can’t be neglected. Therefore, it is important for seismic protection, disaster prevention and mitigation of earthen ruins to analyze seismic stability and conduct safety evaluation of soil sites.Taking the national key protecting cultural relics in Gaotai of Gansu province—earthen ruins of Camel city as a example, through field investigation, site mapping, references research and other ways, engineering geology and geotechnical engineering of earthen ruins in Camel city are clarified; the disease characteristics and formation mechanism are analyzed. The basic physical parameter and mechanical parameters of earthen ruins are obtained by in-situ dynamic test, indoor test, references research. The calculating parameters are counted utilizing MATLAB numerical software. Through numerical simulation, the following analysis are conducted respectively for earthen ruins in Camel city, including modal analysis, instantaneous dynamics analysis, pseudo dynamic reliability and dynamic reliability analysis, sensitivity, and correlation analysis. Finally, taking the damage threshold as criteria, the generally regular conclusions of stability for earthen ruins in Camel city under seismic load is drawn. The main progress and results of this thesis are specifically as follows:1. The engineering geology and geotechnical engineering conditions including climate, hydrology, geology, seismic activity and so on within the scope of the areas of earthen ruins in Camel city, in addition, the architectural form, disease characteristics, diseases causing and protection status of earthen ruins in Camel city are clarified.2. Conventionally physical parameter and dynamical parameters of building materials of earthen ruins in Camel city are gained, including mode of vibration, natural frequency, wave velocity, elastic modulus, damping ratio, poisson ratio, shear strength and material limit stress, etc.3. Based on the theory of ground vibration energy distribution, the computing efficiency is improved effectively by making use of wavelet optimization method which designs the input ground vibration using wavelet algorithm. Computing method of stochastic finite element method is meliorated on the foundation of ensuring computing precision. Furthermore, the reliability of optimizing calculation method is verified through calculating three-story frame structure by utilizing the mode of decomposition method.4. The modal characteristics of earthen ruins in Camel city with different boundary constraint are calculated. The basic distribution characteristics and changing regularity of displacement field, acceleration and stress field of walls with different intensity, the possible damage mode of earthen ruins and failure condition are analyzed.5. The applicability and advantage of probability and statistics theory method applied to seismic stability research for earthen ruins are comprehensively analyzed. The improved pseudo dynamic reliability and dynamic reliability are introduced to study seismic stability of earthen ruins; the judging method associated test data and computing results for seismic stability of earthen ruins is established.6. Through calculating the correlation and sensitivity of random input and output variables based on certain distribution characteristics, the impact manner and degree of seismic forces, wall density, material Poisson ratio and the relatively independent length of wall on seismic stability properties of earthen ruins is analyzed.This paper is financed by Gansu province scientific support plan (0708NKCF089) funding.更多还原