Prestressed concrete cylinder pipe (PCCP) is a critical type of pressure pipe widely used in major water conveyance projects worldwide. As essential components of a PCCP, the mortar coating and concrete core are directly linked to its operational safety. This study employed piezoelectric lead zirconate titanate (PZT) devices as transducers to generate excitation vibrations and measure the resulting Rayleigh waves, thereby providing a means to detect cracking in and monitor the health of the mortar coating and concrete core of a prototype 1400 mm inner-diameter PCCP under external pressure. First, a theoretical analysis was conducted to define the propagation laws of Rayleigh waves. Next, a finite element analysis was undertaken to identify the tensile regions of the PCCP mortar coating and concrete core when under external pressure applied along the length of the PCCP and thereby establish the locations for the PZT devices. Experiments were subsequently conducted by incrementally increasing the external pressure load from 0 to 700 kN while monitoring the cracking in the mortar coating and concrete core using sinusoidal excitation signals with frequencies of 5, 10, and 20 kHz. The voltage amplitudes measured at each external pressure load were analysed, confirming the Rayleigh wave propagation laws and revealing that the change in the measured voltage amplitude curve aligned with the experimental observations, thereby validating the proposed measurement method. Finally, the relative percentage deviation of amplitude (RPDA) and relative percentage deviation of energy (RPDE) damage indices were established based on the voltage measurements to further evaluate the damage state of the mortar coating and concrete core. The RPDA measured at an excitation frequency of 20 kHz was best for detecting cracks in the PCCP mortar coating, whereas the RPDA and RPDE measured at excitation frequencies of 20 and 10 kHz, respectively, were best for monitoring concrete core cracking.

中文翻译：

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使用压电锆钛酸铅对预应力混凝土圆筒管上的砂浆涂层和混凝土芯裂缝进行外部压力下基于瑞利波的监测


预应力混凝土圆筒管 （PCCP） 是一种关键类型的压力管，广泛用于全球主要输水项目。作为 PCCP 的重要组成部分，砂浆涂层和混凝土芯材与其操作安全直接相关。本研究采用压电锆钛酸铅 （PZT） 器件作为传感器来产生激励振动并测量产生的瑞利波，从而提供了一种在外部压力下检测 1400 mm 内径 PCCP 原型的砂浆涂层和混凝土芯的开裂和监测健康状况的方法。首先，进行了理论分析以定义瑞利波的传播规律。接下来，进行了有限元分析，以确定沿 PCCP 长度施加外部压力时 PCCP 砂浆涂层和混凝土核心的拉伸区域，从而确定 PZT 装置的位置。随后通过将外部压力载荷从 0 逐渐增加到 700 kN 进行实验，同时使用频率为 5、10 和 20 kHz 的正弦激励信号监测砂浆涂层和混凝土核心的开裂。分析了在每个外部压力负载下测得的电压幅值，证实了瑞利波传播规律，并揭示了测得的电压幅值曲线的变化与实验观察结果一致，从而验证了所提出的测量方法。最后，基于电压测量建立振幅相对百分比偏差 （RPDA） 和能量相对百分比偏差 （RPDE） 损伤指数，以进一步评价砂浆涂层和混凝土核心的损伤状态。 在 20 kHz 激励频率下测得的 RPDA 最适合检测 PCCP 砂浆涂层中的裂缝，而在 20 kHz 和 10 kHz 的激发频率下测得的 RPDA 和 RPDE 最适合监测混凝土芯开裂。