基于声频阈值估计的混凝土空洞快速识别方法研究

A fast recognition method of concrete void based on acoustic frequency threshold estimation

传统的声振技术在实际工程应用中普遍存在识别参数模糊、操作过程复杂等诸多问题,针对该问题本文提出了基于声频阈值估计的混凝土空洞快速识别方法。使用comsol软件建立声固耦合有限元模型,对多种工况的空洞模型进行了数值模拟,得到了声压、频率等相关参数的变化规律,提出了基于空气耦合冲击回波法的混凝土空洞识别参数,并结合物理模型试验进一步进行探索验证。研究表明,相比于空洞深度,空洞宽度对声波基频的影响显著提高,当空洞宽度C>0.35 m时,一阶模态成为主导模态,声波基频随空洞宽度增加而减小,变化比较明显。基于空气耦合技术的检测方法可以有效识别宽度大于0.35 m的空洞病害,利用本研究中的识别参数可以对混凝土结构中深度0.4 m以内的空洞情况进行快速有效的识别。该研究成果将有利于隧道、桥梁等混凝土结构的损伤检测与状态评估。

Traditional acoustic vibration technology has many problems in practical engineering applications,such as fuzzy identification parameters,complex operation process,etc.In order to solve this problem,a fast identification method of concrete void based on acoustic frequency threshold estimation was proposed in this paper.A acoustic-solid coupling finite element model was established by using Comsol software,and the void model under various work conditions was numerically simulated,and the changing rules of sound pressure,frequency,and other related parameters were obtained.The void identification parameters of concrete based on an air-coupled impact echo method were proposed and further explored and verified by physical model tests.The research shows that compared with the depth of the void,the influence of the void width on the fundamental frequency of the acoustic wave was significantly improved.When width C>0.35 m,the first mode becomes the dominant mode,and the fundamental frequency of the sound wave decreases with the increase of the void width,and the change is obvious.The method based on the air coupling technology can effectively identify the void with a width greater than 0.35 m,The identification parameters in this study can be used to quickly and effectively identify the cavity in the concrete structure with a depth of less than 0.4 m.The research results will be beneficial to the damage detection and state assessment of concrete structures such as tunnels and bridges.