堆石料残余变形模型研究

发布时间：2018-02-24 03:17

本文关键词： 三轴试验堆石料残余变形数值分析　出处：《大连理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：我国土石坝主要建设在地震基本烈度高、地质条件复杂、水资源丰富的西南地区,如果遭受震害将造成巨大损失。已有的资料显示大多数震害都与残余变形有关,因此需要深入研究筑坝堆石料的残余变形特性。如何预测坝体的残余变形已成为土石坝设计中的一个关键问题。目前国内外众多学者已经在残余变形方面做了大量研究分析工作,主要的方法是通过大量的试验来建立能反映堆石料残余变形特性的计算模型,从而对土石坝进行计算分析。不同残余变形模型考虑的影响因素不同,将导致其计算结果存在一定差异,计算模型不仅要能考虑不同振次、不同围压、不同应力水平等试验条件,而且模型本身必须概念清晰,应用简捷,参数求取方便。本文在国家自然科学基金“筑坝堆石料的剪胀特性及其对高面板堆石坝静、动力变形的影响研究”(编号：51279025)和“强震时超高面板坝面板破损机理及其抗震对策研究”(编号：51379028)、国家自然科学基金重大研究计划集成项目“高土石坝地震灾变过程模拟与集成研究”(编号：91215301)、地震行业科研专项经费项目(编号：201208013)以及新世纪优秀人才支持计划“高土石坝和核电厂工程抗震”(编号：NCET-2012-12-0083)的资助下,就残余变形模型目前存在的问题进行了研究,主要工作如下： (1)利用大型静、动两用三轴仪,对某拟建高面板堆石坝的筑坝材料进行了大量的动力循环三轴试验,并整理出模型参数,为数值分析提供依据。 (2)分析了堆石料残余变形过程中泊松比的特性,泊松比在初始变化较大,但随着振次或轴向应变的增加泊松比的数值逐渐增大并趋于稳定。根据试验结果整理出泊松比与动应力比、固结比、围压的关系以及其分布范围。整理残余剪应变时不应假定泊松比不变,应根据体变和轴向应变计算残余剪应变和循环剪应变。 (3)整理、统计已有的残余变形模型,针对已有模型存在的问题,提出采用双曲线表述残余应变与振次的关系,分别在残余体应变关系式和残余剪应变关系式中引入平均主应力和固结比,能更好地反映坝体的残余变形特性。 (4)分别采用建议残余变形模型与常用模型进行数值模拟,分析了不同模型之间的差异,进一步验证了本文提出模型的合理性。
[Abstract]:Earth-rock dams in China are mainly built in southwest areas with high earthquake intensity, complicated geological conditions and abundant water resources. If they are affected by earthquakes, they will cause huge losses. Most of the existing data show that most of the earthquake disasters are related to residual deformation. Therefore, it is necessary to deeply study the residual deformation characteristics of rockfill. How to predict the residual deformation of dam body has become a key problem in the design of earth-rock dam. At present, many scholars at home and abroad have done a lot of research and analysis on residual deformation. The main method is to establish a calculation model which can reflect the residual deformation characteristics of rockfill through a large number of experiments. Therefore, the calculation and analysis of earth-rock dam are carried out. Different residual deformation models consider different influencing factors, which will lead to some differences in calculation results. The calculation model should not only be able to consider different vibration times and confining pressures. Different stress levels and other test conditions, and the model itself must be clear concept, simple application, easy to obtain parameters. In this paper, the shear-dilatancy characteristics of rockfill materials for dam construction and its static effect on high face rockfill dam are studied by the National Natural Science Foundation of the people's Republic of China. Study on the influence of dynamic deformation "(No. 51279025) and" study on the damage Mechanism and Seismic Countermeasure of Ultra High face concrete face Dam under strong earthquake "(No. 51379028)," earthquake disaster process of High Earth-Rock Dam ", an Integrated Project of National Natural Science Foundation of China. Research on Simulation and Integration (No. 91215301), supported by a special research project for the earthquake industry (No.: 201208013) and the New Century Talent support Program, "Earth-Rock Dam and Nuclear Power Plant Project earthquake Resistance" (No.: NCET-2012-12-0083), The existing problems of residual deformation model are studied. The main work is as follows:. 1) A large number of dynamic cyclic triaxial tests are carried out on a dam material of a high face rockfill dam by using a large static and dynamic triaxial instrument, and the model parameters are sorted out, which provides a basis for numerical analysis. The characteristics of Poisson's ratio in the process of residual deformation of rockfill are analyzed. However, with the increase of vibration frequency or axial strain, the Poisson's ratio increases gradually and tends to be stable. According to the experimental results, the Poisson's ratio, the dynamic stress ratio and the consolidation ratio are sorted out. The relation of confining pressure and its distribution range. Poisson's ratio should not be assumed to be invariant in finishing residual shear strain, but residual shear strain and cyclic shear strain should be calculated according to bulk strain and axial strain. In order to solve the problems of the existing models, a hyperbolic method is proposed to describe the relationship between residual strain and vibration frequency. The average principal stress and consolidation ratio are introduced into the residual body strain relationship and the residual shear strain relationship, respectively, which can better reflect the residual deformation characteristics of the dam body. (4) the proposed residual deformation model and the common model are used to simulate the model, and the differences between different models are analyzed, which further verifies the rationality of the proposed model.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV41

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