低温沥青混凝土静三轴试验研究及沥青心墙堆石坝有限元计算分析

发布时间：2018-04-30 06:05

本文选题：土石坝 + 沥青混凝土心墙　；参考：《西安理工大学》2017年硕士论文

【摘要】：随着我国水利开发建设难度的加大,建设环境在朝着低温、高海拔、多震地带发展,沥青混凝土心墙堆石坝作为能够适应复杂地质条件的一种坝型被广泛应用于我国西北、西南和东北等自然条件恶劣地区的水工建设。为适应建设的新需要,深入研究沥青混凝土在低温环境下的力学特性和应变情况显得十分迫切。首先,从水工沥青混凝土的组成结构出发,介绍了各组成材料的作用,通过检测试验选出满足寒冷地区工程建设需要的材料。运用单因素分析法处理劈裂试验结果,综合分析空隙率、劈裂位移、劈裂强度与油石比、填料浓度、级配指数的关系,选出一组作为三轴试验配合比。其次,设计了低温和常温共三组三轴试验。试验用两组常温试验作为低温组试验的参照,深入剖析沥青混凝土在低温环境下的力学特性和应力应变的规律。本次试验运用Duncan-Chang E-B模型进行力学计算,摩尔-库仑理论为强度破坏准则。在求解模型参数K、n和Rf时,根据应力-应变曲线特点,引用置信度和反算拟合应力应变曲线对两点法、全部法和分段法的适用性进行了综合比较,优化K、n和Rf的求解方法,减小了人为因素对参数的影响。最终得出结论:温度越低,沥青混凝土的强度越大,选取60%~95%应力水平试验点参与计算的方法最适合计算低温沥青混凝土静三轴试验力学模型参数。最后,以高寒地区某电站为研究对象,把不同试验温度下得到的沥青混凝土邓肯-张E-B参数分别代入有限元模型进行计算,分析不同试验温度下得到的参数对坝体和心墙的应力应变计算的影响。结果表明,低温组心墙应力出现上拱效应,分析结果偏于危险,对混凝土配合比的要求更高。本次研究为沥青混凝土三轴试验的数据处理奠定了一定的理论基础,对分析温度对沥青混凝土性能的影响有借鉴价值,所获得的计算成果对同类工程有重要的参考意义。
[Abstract]:With the increasing difficulty of water conservancy development and construction in our country, the construction environment is developing towards low temperature, high altitude and multi-earthquake zone. As a dam type which can adapt to complex geological conditions, bituminous concrete core wall rockfill dam is widely used in northwest China. Hydraulic construction in areas with harsh natural conditions such as southwest and northeast China. In order to meet the new needs of construction, it is very urgent to study the mechanical properties and strain of asphalt concrete in low temperature environment. Firstly, starting from the composition structure of hydraulic asphalt concrete, this paper introduces the function of each component material, and selects the materials to meet the need of engineering construction in cold area by testing and testing. The single factor analysis method is used to deal with the results of split test. The relationship between porosity, split displacement, splitting strength and the ratio of stone to stone, packing concentration and gradation index is analyzed comprehensively, and a group is selected as the mixture ratio of triaxial test. Secondly, three groups of triaxial tests were designed at low temperature and normal temperature. The mechanical properties and stress-strain laws of asphalt concrete under low temperature environment were analyzed by using two sets of normal temperature test as the reference of low temperature group test. In this experiment, Duncan-Chang E-B model is used for mechanical calculation, and Mohr-Coulomb theory is used as strength failure criterion. According to the characteristics of stress-strain curve, the applicability of two-point method, total method and piecewise method are compared synthetically according to the characteristics of stress-strain curve in solving model parameters K _ n and R _ f, and the two point method, the whole method and the piecewise method are compared synthetically, and the solution method of K _ (n) and R _ (f) is optimized. The influence of human factors on the parameters is reduced. Finally, it is concluded that the lower the temperature, the greater the strength of asphalt concrete. The method of 60% 95% stress level test point is the most suitable method to calculate the mechanical model parameters of static triaxial test of low temperature asphalt concrete. Finally, taking a power station in the high and cold region as the research object, the parameters of Duncan Zhang E-B obtained from asphalt concrete at different test temperatures are calculated by means of finite element model. The influence of the parameters obtained at different test temperatures on the calculation of stress and strain of dam and core wall is analyzed. The results show that the stress of low temperature core wall has the effect of upper arch, the analysis result is more dangerous, and the requirement of concrete mix ratio is higher. This study lays a certain theoretical foundation for the data processing of asphalt concrete triaxial test and has reference value for analyzing the influence of temperature on the performance of asphalt concrete. The results obtained are of great reference significance to similar projects.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV641.41;TV431

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