中文摘要：

针对矩形网格模型的声波层析成像检测结构混凝土存在的主要问题：1）矩形网格无法充分模拟结构混凝土的速度间断面、2）射线追踪面临穿到凹多边形检测区域之外或穿越内部预留空洞的风险,本文研究了三角网声波层析成像检测技术.依据Delaunay三角剖分的优化准则,结合波前法对模型进行三角剖分;采用＂基于波前最小走时单元的三角网射线追踪全局算法＂计算声波初至时、追踪射线路径;应用代数重构技术求解层析成像反演控制方程,得到模型的速度分布.数值模拟及应用实例表明,三角网声波层析成像,模型参数化灵活、速度间断面描述准确,射线追踪可靠性强、精度高,反演成像分辨率高、更接近实际结构形态,适应具有复杂几何边界和内部结构的结构混凝土的质量检测.

英文摘要：

There are two main problems for sonic computerized tomography when detecting the complex structural concrete using rectangular grid model,one is insufficient simulating the velocity interfaces,the other is that the raypath may be outside the concave polygon area or pass through the reserved inner cave. Triangular grid sonic computerized tomography is presented in this paper.The model triangulation is based on an optimal criterion of Delaunay triangulation combined with wave front method.The first arrival time is calculated and the raypath is traced by using aglobal algorithm of triangular grid ray tracing method based on wavefront minimum traveltime unit.The model velocity distribution is obtained by solving the inversion controlled equation of computerized tomography using algebra reconstruction technology. Numerical simulation results and case histories show that the triangular grid sonic computerized tomography is high flexibility for model parameter and high accuracy of description of velocity interfaces,high raytracing reliability and accuracy. The inversion image has high resolution and more closed to the actual structure.The technique is suitable for detecting the quality of concrete with complex boundary and complex inner structure.