The constant velocity one-dimensional wave theory has been commonly used to determine the pile lengths from the impulse response testing results for several years. In this paper, the three-dimensional guided wave theory was introduced to extract more information from the impulse response spectra on five concrete piles. Combined with resonance concept, this guided wave-based approach was developed to simply and efficiently identify the length estimates with 3% or less errors, similar to those of the conventional one-dimensional wave-based approach. Moreover, the guided wave theory provides more individual resonant frequencies insight over that of the one-dimensional wave theory. All the experimental phase velocities at their corresponding resonant frequencies have a good consistency with the guided wave prediction curve at frequencies up to 5000 Hz. The resulting scattering also presents a slightly decrease trend with frequency. The overall analysis indicates that the guided wave theory can give more useful information than that of the one-dimensional wave theory. In future, one can use this inverse computation approach to evaluate unknown pile lengths.

中文翻译：

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用导波法估算脉冲响应测试的桩长

多年来，等速一维波浪理论已被普遍用于根据脉冲响应测试结果确定桩长。在本文中，引入三维导波理论从五个混凝土桩的脉冲响应谱中提取更多信息。结合共振概念，开发了这种基于导波的方法，以简单有效地识别长度估计，误差为 3% 或更少，类似于传统的基于一维波的方法。此外，导波理论提供了比一维波理论更多的单独谐振频率洞察力。所有在其相应谐振频率下的实验相速度与频率高达 5000 Hz 的导波预测曲线具有良好的一致性。由此产生的散射也呈现出随频率略微下降的趋势。总体分析表明，导波理论比一维波理论可以提供更多有用的信息。将来，人们可以使用这种逆向计算方法来评估未知的桩长。