桥梁检测中非结构化网格层析正演算法研究

Research on unstructured grid tomography forward technology in bridge inspection

在桥梁检测中弹性波层析正演是关键步骤。常规的层析正演中通常采用射线追踪算法,由于受规则矩形网格的影响,存在射线不能覆盖的异常区,射线旅行时误差曲线波动较大,进而导致累积误差较大,不利于进一步数值分析与校正。这里利用自适应三角网剖分技术,结合线性插值射线旅行时算法,分别对规则匀速模型、非规则匀速和变速模型进行试算,其射线路径分布结果和旅行时误差曲线结果,表明了该算法的正确性与可靠的计算精度,印证其算法对桥梁内部缺陷的检测是可靠的。

Elastic wave tomography forward modeling is a key step in bridge detection.In conventional tomography forward modeling,ray tracing algorithm is usually used.Because of the influence of regular rectangular meshes,there are anomalous areas that can't be covered by ray,and the error curve of ray travel time fluctuates greatly.This leads to large cumulative error and being not conducive to further numerical analysis and correction.In this paper,the adaptive triangulation technique and the linear interpolation ray travel time algorithm are used to calculate the regular uniform speed model,the irregular uniform speed model and the speed model respectively.The results of the ray path distribution and the travel time error curve show the correctness and reliability of the algorithm.This proves that the algorithm is reliable in detecting the internal defects of bridges.