混凝土构件空洞模拟检测试验与ARMA功率谱分析

及时发现空洞隐患、确定空洞大小,准确评估不良病害的危害程度对指导施工和提高混凝土结构质量具有重要意义。为实现空洞尺寸的量化,对试验模型中的模拟空洞进行地质雷达检测,应用基于SVD-TLS方法的ARMA功率谱分析对原始数据进行处理。结果表明:地质雷达探测区域覆盖的空洞范围越大,空洞信号越明显。基于SVD-TLS方法的ARMA功率谱分析具有较高的分辨率,可以识别异常反射信息,判断空洞在测线方向的范围;功率谱参数期望值有一定的分布范围,当参数期望值在-0.160以下时,可以基本确定为空洞区域。最后结合工程实例,对地质雷达数据进行功率谱分析,取得了良好的效果。该分析方法为研究混凝土构件内部空洞的检测提供了新途径,一定程度上实现了空洞尺寸的量化。

Simulation Test and ARMA Power Spectrum Analysis for Detection Signal of Cavity in Concrete Member

Finding the size of cavity defect and assessing the extent of damages accurately are important to guide construction and improve the quality of concrete structures. The simulation cavity testing in experimental model was carried out using ground penetrating radar (GPR). Moreover, the signal ARMA power spectrum analysis was performed through singular value decomposition and total least square(SVD-TLS) method to distinguish the quantification of cavity size. The results show that cavity signal becomes more obvious when GPR detection zone in the cavity increases. ARMA power spectrum analysis can identify abnormal reflection information and judge cavity range in the detecting direction with high resolution. The power spectrum parameter expectations have a certain distribution. The detection zone can be determined as a cavity when the parameter expectation is lower than -0.160. Finally, the GPR data in a practical project were well analyzed by power spectrum analysis. A new way was put forward for cavity detection, and the quantification of cavity size in concrete member was achieved to some extent.