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采用各种探测手段揭示目标介质内部构造的信息一直是工程界所关心的重要课题。以弹性波在不同介质交界面传递特性为理论基础,明晰冲击映像检测方法的基本原理。采用有限差分数值模拟方法,针对含有低速夹层的水平层状介质模型,获得各工况下响应波形数据,并对其进行振幅大小、主频能量及时频分析,从而揭示当低速夹层介质的物理参数改变时,在模型表面一定位置所接收到的响应波形的振幅、频谱及时频的变化规律,验证冲击映像检测方法有效性和精确性。在数值计算的基础上,将冲击映像法应用于天津滨海海河沉管隧道底板注浆效果检测分析,根据现场采集的实测响应波形数据,通过对响应波形可视化处理、频谱分析及时频分析,比较注浆前、后的弹性波特性变化,实现对沉管隧道底板注浆效果的综合评价,获得了良好的检测效果。
It has always been an important topic of engineering concern that using various detection methods to reveal the information about the internal structure of the target medium. Based on the theoretical basis of the transmission characteristics of elastic waves at different media interfaces, the basic principle of impact image detection method is clarified. The finite difference numerical simulation method is applied to the horizontal layered medium model with low velocity interlayer to obtain the response waveform data of each working condition. The amplitude, frequency energy and time-frequency analysis are also conducted to reveal the physical parameters When changing, the variation of amplitude, frequency spectrum and time-frequency of the response waveform received at a certain position on the surface of the model verifies the validity and accuracy of the impact image detection method. Based on the numerical calculation, the impact mapping method is applied to the grouting effect detection and analysis of the floor of the immersed tunnel in Tianjin Binhai Haihe River. According to the measured response waveform data collected in the field, through the visualization of response waveforms, spectrum analysis and time-frequency analysis, Before and after the change of elastic wave characteristics, to achieve the comprehensive evaluation of grouting effect of immersed tunnel floor, get a good test results.