基于超声波声学参数的钢管混凝土密实特征参数分析

Analysis for the Compactness Characteristic Parameters of CFST Based on Ultrasonic Acoustic Parameters

基于超声波检测技术可以评估钢管混凝土的密实性,为研究混凝土抗压强度、检测龄期、钢管直径等特征参数与超声波声学参数之间的相关性影响,开展5座钢管混凝土拱桥现场检测以及7个钢管混凝土试件中252组检测试验,结合K-S检验(Kolmogorov-Smirnov test)和相关性分析,确定超声波声学参数样本数据的分布类型,合理遴选声学参数与特征参数之间的最优参数组合,进而分别建立了声学参数与特征参数之间的定量关系。研究结果表明:声学参数样本数据的统计分布规律大都服从正态分布,且随着检测龄期增大,声学参数样本数据的统计分布规律呈现增大且趋于收敛;与其他测区相比,当测区内存在加劲板、法兰盘等管内钢结构时,超声波波速增幅可达3%~5%,波幅和频率折减分别可达12%~18%和15%~20%;声学参数与混凝土抗压强度、检测龄期和钢管直径之间的相关性较大,随着混凝土抗压强度和检测龄期增大分别呈线性增大和对数增大趋势,而随着钢管直径增大呈对数减小趋势。

Using ultrasonic testing technology,the compactness of concrete filled steel tubes(CFST)can be measured.Field tests were conducted on five CFST arch bridges and 252 groups of seven CFST specimens in order to examine the correlation between characteristics such as compressive strength of concrete,detection age,diameter of steel pipe and ultrasonic acoustic parameters.Then the distribution type of ultrasonic acoustic parameter sample data was determined based on the K-S test(Kolmogorov-Smirnov test).In addition,the optimal parameter combination of the ultrasonic acoustic parameter and the characteristic parameter was determined by the correlation analysis,and the quantitative relationship between the ultrasonic acoustic parameter and the characteristic parameter was established.Analysis shows that the statistical distribution of ultrasonic acoustic parameters generally follows a normal distribution.Additionally,as the detection age increases,the statistical distribution of ultrasonic acoustic parameters tends to increase and is typically convergent.When there are in-pipe steel structures,such as stiffening plates and flanges,in the survey area,the ultrasonic wave velocity may be slightly increased by 3%to 5%,while the amplitude and frequency may be reduced by 12%to 18%and 18%to 20%.Ultrasonic acoustic parameters have a strong correlation with compressive strength of concrete,detection age,and diameter of steel pipe.It means that ultrasonic acoustic parameters increases linearly and logarithmically with the increase of compressive strength of concrete and detection age,respectively,and then decrease logarithmically with the increase of diameter of steel pipe.