A grout layer between precast concrete components in an assembly structure is required to bear high axial loads and withstand significant shear forces during earthquakes. Since the grout layer usually exists in a narrow space, examining the quality of the layer, particularly detecting debonding at the interface, is a difficult task. However, a debonding defect at the interface is likely to significantly reduce the safety performance of structures. To address this problem, this paper presents a combined experimental and numerical study to detect the interfacial debonding based on the impact-echo theory. Two precast concrete shear walls assembled in a structure were tested by the impact-echo method based on two different boundaries. It is shown that the thickness frequencies near a free boundary are considerably lower than those near a fixed boundary, and the boundary effect disappears when the impact position is far away from the free boundary or the fixed boundary. Such characteristics can be used to identify a debonded layer (i.e., approaching the free boundary) in the grouted joint. A blind in-situ test was also conducted to validate the effectiveness of the proposed impact echo method in detecting debonded layers.

装配结构中预制混凝土构件之间的灌浆层需要承受高轴向载荷并在地震期间承受显着的剪切力。由于灌浆层通常存在于狭窄的空间中，因此检查层的质量，特别是检测界面处的脱粘是一项艰巨的任务。然而，界面处的脱粘缺陷可能会显着降低结构的安全性能。为了解决这个问题，本文提出了一种基于冲击回波理论的结合实验和数值研究来检测界面脱粘的方法。通过基于两个不同边界的冲击回波方法对组装在结构中的两个预制混凝土剪力墙进行了测试。结果表明，自由边界附近的厚度频率明显低于固定边界附近的厚度频率，当撞击位置远离自由边界或固定边界时，边界效应消失。此类特征可用于识别灌浆接头中的脱粘层（即接近自由边界）。还进行了盲原位测试，以验证所提出的冲击回波方法在检测脱粘层方面的有效性。