基于剪切波速变化评估场道水泥混凝土面层弯拉模量

发布时间：2019-03-01 13:33

【摘要】：随着民航事业的高速发展,机场中飞行器数量和航班量迅速增加,机场混凝土道面因承载力不足而出现损坏的现象时有发生。为此,需定期对混凝土道面强度进行检测。作为道面重要评价指标之一的混凝土抗弯拉弹性模量,其传统的破坏型钻芯检测获取方式会损坏道面,而无损检测中的FWD技术仪器笨重,检测成本高,两种方式均不便于在场道测试中广泛使用。剪切波只能在固体介质中传播,其在传播过程中能够携带关于介质的的物理力学性质,并且获取方式简便快捷。可通过建立剪切波速和混凝土道面面层力学参数——弯拉弹性模量之间的关系模型来评价机场道面的物理力学性质。本文基于小挠度薄板理论提出了水泥混凝土道面板中剪切波速和弯拉弹性模量关系的理论模型。同时,以ABAQUS中混凝土的塑性损伤模型为依托,模拟并提取不同等级标号和弹性模量的混凝土小梁试件三分点加载过程中的弯曲应力-应变曲线来获得混凝土弯拉弹性模量。在此基础上,建立了以弹性模量为关联的弯拉模量与弹性波基础理论中的剪切波速的数学关系模型。在实验室通过制作不同等级标号的水泥混凝土标准试件,测试了其在标准养护龄期后瑞雷波的传播速度,并换算成剪切波波速值。利用试验获得的剪切波速值和弯拉弹性模量值对理论分析模型和有限元数学模型进行对比分析。通过试验测试数据对理论模型和有限元模型的对比分析发现,有限元模型相对更接近实际测试情况,其与试验相对误差约为8.13%。验证了有限元仿真剪切波速评价机场道面弯拉弹性模量模型的可行性,进而为实际工程应用中利用剪切波速进行混凝土道面板的无损检测方式提供相关依据和理论指导。
[Abstract]:With the rapid development of civil aviation, the number of aircraft and the number of flights in the airport are increasing rapidly. The damage of the concrete pavement of the airport is sometimes caused by the lack of bearing capacity. Therefore, it is necessary to test the strength of concrete pavement on a regular basis. As one of the important indexes of pavement evaluation, the flexural tensile elastic modulus of concrete can be damaged by the traditional destructive core detection and acquisition method. However, the FWD technology instrument in non-destructive testing is bulky and the testing cost is high. Both methods are not easy to be widely used in field channel testing. The shear wave can only propagate in solid medium, it can carry the physical and mechanical properties of the medium in the process of propagation, and the acquisition method is simple and quick. The physical and mechanical properties of the airport pavement can be evaluated by establishing the relationship model between the shear wave velocity and the mechanical parameters of the concrete pavement, that is, the flexural tensile modulus of elasticity. Based on the theory of thin plates with small deflection, a theoretical model of the relationship between shear wave velocity and elastic modulus of flexural tension in cement concrete pavement slab is presented in this paper. At the same time, based on the plastic damage model of concrete in ABAQUS, the bending stress-strain curves of concrete beams with different grades and elastic modulus are simulated and extracted to obtain the flexural tensile elastic modulus of concrete. On the basis of this, a mathematical model of the relationship between the elastic modulus and the shear wave velocity in the basic theory of elastic wave is established. In the laboratory, the propagation velocity of Rayleigh wave after standard curing age was measured by making standard specimens of cement concrete with different grades, and the velocity of shear wave was converted to the value of shear wave velocity. The theoretical analysis model and the finite element mathematical model are compared and analyzed by using the shear wave velocity value and the flexural tensile elastic modulus value obtained from the experiment. Through the comparative analysis of the theoretical model and the finite element model from the test data, it is found that the finite element model is closer to the actual test condition, and the relative error between the finite element model and the experiment is about 8.13%. The feasibility of finite element simulation of shear wave velocity to evaluate the elastic modulus model of airport pavement is verified, which provides the relevant basis and theoretical guidance for the non-destructive testing of concrete slab by shear wave velocity in practical engineering.
【学位授予单位】：中国民航大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.216;V351.11

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