水工沥青混凝土力学性能试验研究
发布时间：2018-12-16 23:50
【摘要】：沥青混凝土作为土石坝的防渗系统，在世界范围内得到了广泛运用。但作为新兴的水工防渗结构，随着坝高越来越高，其安全稳定性必须引起足够的重视，因此对于沥青混凝土心墙材料基本力学性能方面的研究就显得很重要。本文通过静三轴试验对不同条件下的沥青混凝土心墙材料的强度及变形特性进行了研究，得到了沥青混凝土心墙材料力学性能的一些规律。主要研究工作及成果如下： 1、以沥青混凝土心墙堆石坝为主题，系统地介绍了目前大坝的设计与建设现状，，总结了前人在沥青混凝土力学性能研究方面的成果和不足，在此基础上进行了不同成型工艺及不同温度、加载速率条件下的沥青混凝土静三轴试验，研究沥青混凝土的基本力学性能，为工程应用奠定基础。 2、利用正交表对初选配合比试验进行正交设计，然后对设计的试验方案进行试验，利用正交设计中极差分析法对试验结果进行计算分析，并选出最优配合比，为本文开展的力学试验提供了科学基础。 3、沥青混凝土的力学性能对试验温度、围压等试验条件比较敏感。同等试验条件下，试验温度越低，沥青混凝土破坏强度越高，初始切线模量越大，轴向破坏应变越小；围压越高，沥青混凝土破坏强度越高，剪胀程度越小。 4、在沥青混凝土配合比、试验温度、围压一定的试验条件下，由于压实机理不同，静压成型相较击实成型的沥青混凝土三轴试验应力-应变曲线的峰值强度更高，初始切线模量更大，剪胀现象更加明显。 5、剪切速率对沥青混凝土三轴试验结果的影响在不同的围压试验条件下表现出相似的规律性：剪切速率越大，试样剪胀越明显，破坏强度越高，且破坏强度随剪切速率增长的速率基本一致。 6、沥青混凝土心墙作为大坝的防渗体是一个隐蔽性结构，目前对于土石坝沥青混凝土心墙在自然环境温度变化的循环条件下对沥青混凝土力学性能的影响问题的研究还较少。本文通过在冷热循环工艺条件下模拟沥青混凝土试样受温度的循环变化，并通过三轴剪切试验来反映沥青混凝土试样力学性能的变化。试验结果初步表明经过温度循环后的沥青混凝土破坏强度均出现了降低现象。 7、最后分别用邓肯-张模型、凤家骥修正双曲线模型与南水非线性模型来描述沥青混凝土心墙材料的应力-应变关系，并将拟合结果进行了对比分析。从对比结果可以看出，在本次试验研究中南水非线性模型能更好地描述沥青混凝土心墙材料的应力-应变关系。
[Abstract]:As a seepage control system of earth-rock dam, asphalt concrete has been widely used in the world. However, as a new hydraulic anti-seepage structure, with the dam height increasing, its safety and stability must be paid enough attention to, so it is very important to study the basic mechanical properties of asphalt concrete core wall materials. In this paper, the strength and deformation characteristics of asphalt concrete core wall materials under different conditions are studied by static triaxial test, and some laws of mechanical properties of asphalt concrete core wall materials are obtained. The main research work and achievements are as follows: 1. Taking the asphalt concrete core rockfill dam as the theme, this paper systematically introduces the present design and construction status of the dam, and summarizes the achievements and shortcomings of the previous researches on the mechanical properties of asphalt concrete. On this basis, static triaxial tests of asphalt concrete under different forming process, different temperature and loading rate were carried out, and the basic mechanical properties of asphalt concrete were studied, which laid a foundation for engineering application. (2) orthogonal design is carried out on the primary mix ratio test by orthogonal table, then the designed test scheme is tested, the test result is calculated and analyzed by using the range analysis method in the orthogonal design, and the optimum mix ratio is selected. It provides a scientific basis for the mechanical tests carried out in this paper. 3. The mechanical properties of asphalt concrete are sensitive to test temperature and confining pressure. Under the same test conditions, the lower the test temperature, the higher the failure strength of asphalt concrete, the greater the initial tangent modulus, the smaller the axial failure strain, and the higher the confining pressure, the higher the failure strength and the smaller the shear expansion degree of asphalt concrete. 4. Under certain experimental conditions of asphalt concrete mixture ratio, test temperature and confining pressure, because of different compaction mechanism, the peak strength of static pressure forming is higher than that of compacted asphalt concrete triaxial test stress-strain curve. The initial tangent modulus is larger and the shear expansion is more obvious. 5. The effect of shear rate on the triaxial test results of asphalt concrete shows similar regularity under different confining pressure test conditions: the larger the shear rate, the more obvious the shear expansion and the higher the failure strength. The failure strength is basically the same as the shear rate. 6. The asphalt concrete core wall is a concealed structure as the impervious body of the dam. At present, there is little research on the influence of the asphalt concrete core wall on the mechanical properties of the asphalt concrete under the condition of temperature change in the natural environment. In this paper, the temperature cycling of asphalt concrete samples is simulated under the condition of hot and cold cycling, and the mechanical properties of asphalt concrete specimens are reflected by triaxial shear test. The experimental results show that the failure strength of asphalt concrete after temperature cycling has been reduced. Finally, the stress-strain relationship of asphalt concrete core wall is described by Duncan Chang model, Fengjiaji modified hyperbolic model and Nanshui nonlinear model, and the fitting results are compared and analyzed. It can be seen from the comparison results that the nonlinear model of Nanshui in this experiment can better describe the stress-strain relationship of asphalt concrete core wall materials.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV431
本文编号：2383266
[Abstract]:As a seepage control system of earth-rock dam, asphalt concrete has been widely used in the world. However, as a new hydraulic anti-seepage structure, with the dam height increasing, its safety and stability must be paid enough attention to, so it is very important to study the basic mechanical properties of asphalt concrete core wall materials. In this paper, the strength and deformation characteristics of asphalt concrete core wall materials under different conditions are studied by static triaxial test, and some laws of mechanical properties of asphalt concrete core wall materials are obtained. The main research work and achievements are as follows: 1. Taking the asphalt concrete core rockfill dam as the theme, this paper systematically introduces the present design and construction status of the dam, and summarizes the achievements and shortcomings of the previous researches on the mechanical properties of asphalt concrete. On this basis, static triaxial tests of asphalt concrete under different forming process, different temperature and loading rate were carried out, and the basic mechanical properties of asphalt concrete were studied, which laid a foundation for engineering application. (2) orthogonal design is carried out on the primary mix ratio test by orthogonal table, then the designed test scheme is tested, the test result is calculated and analyzed by using the range analysis method in the orthogonal design, and the optimum mix ratio is selected. It provides a scientific basis for the mechanical tests carried out in this paper. 3. The mechanical properties of asphalt concrete are sensitive to test temperature and confining pressure. Under the same test conditions, the lower the test temperature, the higher the failure strength of asphalt concrete, the greater the initial tangent modulus, the smaller the axial failure strain, and the higher the confining pressure, the higher the failure strength and the smaller the shear expansion degree of asphalt concrete. 4. Under certain experimental conditions of asphalt concrete mixture ratio, test temperature and confining pressure, because of different compaction mechanism, the peak strength of static pressure forming is higher than that of compacted asphalt concrete triaxial test stress-strain curve. The initial tangent modulus is larger and the shear expansion is more obvious. 5. The effect of shear rate on the triaxial test results of asphalt concrete shows similar regularity under different confining pressure test conditions: the larger the shear rate, the more obvious the shear expansion and the higher the failure strength. The failure strength is basically the same as the shear rate. 6. The asphalt concrete core wall is a concealed structure as the impervious body of the dam. At present, there is little research on the influence of the asphalt concrete core wall on the mechanical properties of the asphalt concrete under the condition of temperature change in the natural environment. In this paper, the temperature cycling of asphalt concrete samples is simulated under the condition of hot and cold cycling, and the mechanical properties of asphalt concrete specimens are reflected by triaxial shear test. The experimental results show that the failure strength of asphalt concrete after temperature cycling has been reduced. Finally, the stress-strain relationship of asphalt concrete core wall is described by Duncan Chang model, Fengjiaji modified hyperbolic model and Nanshui nonlinear model, and the fitting results are compared and analyzed. It can be seen from the comparison results that the nonlinear model of Nanshui in this experiment can better describe the stress-strain relationship of asphalt concrete core wall materials.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV431
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