基于差分进化算法的混凝土德拜模型的研究

发布时间：2018-07-22 10:41

【摘要】：当今社会,交通在国民经济中占据着非常重要的地位,而混凝土是道路建设中应用最广泛的材料之一。大规模的公路建设完成后,伴随而来的是运营期间的病害治理,而路面积水、塌陷等是影响道路安全最常见的危害。国内外调查研究报到表明,有一定比例的道路,由于渗、漏水及塌陷等病害,对道路交通有严重的威胁,缩小了道路的维护周期和使用寿命,并且影响交通质量。探地雷达无损检测技术由于抗干扰能力强、使用方便、检测速度快、分辨率高、非破坏性等优点,广泛地应用于地下工程领域。探地雷达主要对采集的数据进行预处理,然后通过人工分析进行识别,判定地下目标体的大小、深度和方位等特征参数。本文的理论基础是电磁波在有损耗且色散媒质中的传播规则,采用探地雷达无损检测技术测得实验制混凝土的介电常数,建立与混凝土内部结构和测量数据相符的数学模型。由于差分进化算法可处理复杂的实际优化问题、并行性、鲁棒性、自适应性以及易与其它算法结合等优点,故将其应用到所建模型中的参数优化。时域有限差分方法是应用Yee元胞的空间网格模型,利用中心差商替代微商,将空间连续变量离散化,把电磁场进行规约化,得到二维空间上的时域有限差分方程。在给定初始值和边界条件后,本文选择吸收效果较好的完全匹配层吸收边界,应用时域有限差分方法求解高频电磁波在混凝土中传播的麦克斯韦方程。麦克斯韦方程概括了宏观电磁场的基本性质,它揭示了电场与磁场之间,以及电磁场与电荷、电流之间的相互关系,是一切宏观电磁现象所遵循的普遍规律。本文通过软件GprMax正演数值模拟了实际交通中频繁出现的混凝土空洞、积水、钢筋变形及坍塌等灾害现象,并验证方程解的正确性。数值模拟结果表明:(1)本文建立的关于混凝土特征参数的数学模型是有效的,并且符合混凝土自身结构特征及观测数据;(2)应用差分进化算法优化模型中的参数是有效的,差分进化算法的Matlab编程是可行的;(3)利用时域有限差分方法求得麦克斯韦方程的数值解是可靠的;(4)应用软件GprMax模拟高频电磁波在混凝土媒质中的传播,雷达剖面图能够准确地定位埋藏物的位置、分界面反射波的特征以及空洞、水泡和钢筋等埋藏物反射的强弱。
[Abstract]:Nowadays, traffic occupies a very important position in the national economy, and concrete is one of the most widely used materials in road construction. After the completion of large-scale highway construction, it is accompanied by disease management during the operation period, and the road surface water accumulation and collapse are the most common hazards affecting road safety. The investigation and research at home and abroad show that there is a certain proportion of roads, due to seepage, water leakage and collapse and other diseases, there is a serious threat to road traffic, reduce the maintenance cycle and service life of roads, and affect the quality of traffic. Non-destructive testing technology of ground penetrating radar is widely used in underground engineering field because of its strong anti-jamming ability, convenient use, high detection speed, high resolution, non-destructive and so on. Ground penetrating radar (GPR) mainly preprocesses the collected data and then identifies them by manual analysis to determine the characteristic parameters such as size depth and azimuth of underground objects. The theory of this paper is based on the propagation rules of electromagnetic waves in lossy and dispersive media. The dielectric constant of concrete is measured by using ground-penetrating radar nondestructive testing technique, and a mathematical model consistent with the internal structure of concrete and the measured data is established. Because differential evolution algorithm can deal with complex practical optimization problems, parallelism, robustness, adaptability and easy combination with other algorithms, it is applied to the parameter optimization of the model. The finite-difference time-domain (FDTD) method applies Yee cell's spatial grid model to discretize the spatial continuous variables and normalize the electromagnetic field by using the center difference quotient instead of the differential quotient. The finite-difference time-domain equations in two-dimensional space are obtained by using the finite-difference time-domain (FDTD) method. Given the initial values and the boundary conditions, a perfectly matched layer absorbing boundary is chosen, and the Maxwell equation of high frequency electromagnetic wave propagation in concrete is solved by using the finite difference time-domain method. Maxwell's equation summarizes the basic properties of the macroscopic electromagnetic field, which reveals the relationship between the electric field and the magnetic field, as well as between the electromagnetic field and the charge and the current, which is the universal rule followed by all the macroscopic electromagnetic phenomena. In this paper, through the software GprMax forward numerical simulation, the frequent occurrence of concrete cavities, water accumulation, steel bar deformation and collapse in actual traffic are simulated, and the correctness of the equation solution is verified. The numerical simulation results show that: (1) the mathematical model of concrete characteristic parameters established in this paper is effective and accords with the concrete structural characteristics and observed data; (2) the differential evolution algorithm is used to optimize the parameters in the model. The Matlab programming of differential evolution algorithm is feasible. (3) it is reliable to obtain the numerical solution of Maxwell equation by using finite difference time domain method. (4) the software GprMax is used to simulate the propagation of high frequency electromagnetic wave in concrete medium. Radar profiles can accurately locate the location of buried objects, the characteristics of the reflected waves at the interface, and the reflection of holes, blisters and steel bars.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414;TP18

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