Prestressed concrete cylinder pipes (PCCPs) have been applied for various water conveyance projects recently, especially in long distance. PCCPs not only bear internal water pressures, but also external loads. The excess of external loads may cause major accidents. However, the mechanical behavior of PCCPs under external load is different from that of PCCPs under internal pressure. In this study, a three-edge bearing test (TEBT) of a PCCP was performed to study its mechanical properties under external load. Meanwhile, the fiber Bragg grating (FBG) sensing technology and pulse pre-pump Brillouin optical time-domain analysis (PPP-BOTDA) optical fiber sensing technology were successfully employed to monitor the deformation of PCCPs. The test results show that the deformation of five components of the pipe is proportional to the external load. At the springline of the pipe, the outer concrete core and the prestressing wire are in tension, the inner concrete core and the steel cylinder are in compression. The loading status at the crown and invert of the pipe are opposite with those at the springline of the pipe, but the deformation coordination is consistent. Moreover, the test results demonstrate that PPP-BOTDA-based distributed optical fiber sensors can not only accurately monitor the real-time loading response of the PCCP under the external load like FBG point optical fiber sensors, but also obtain the dynamic and continuous strain distribution of the circumferential section of the pipe. This study has identified the relationship of the external load and deformation, the interaction and strain distribution of each component of PCCPs. This study also confirms that the distributed optical fiber sensing technology can provide an effective means for the structural health monitoring in long-term operation of PCCPs.

预应力混凝土圆筒管（PCCP）最近已用于各种输水工程，特别是在长距离输水工程中。PCCP不仅承受内部水压，而且还承受外部负荷。过多的外部负载可能会导致重大事故。但是，PCCP在外部负载下的机械性能与PCCP在内部压力下的机械性能不同。在这项研究中，进行了PCCP的三边缘轴承测试（TEBT），以研究其在外部载荷下的机械性能。同时，成功地采用了光纤布拉格光栅（FBG）传感技术和脉冲预泵布里渊（Brillouin）光学时域分析（PPP-BOTDA）光纤传感技术来监测PCCP的变形。测试结果表明，管道的五个组件的变形与外部载荷成正比。在管道的弹簧线上，外混凝土芯和预应力钢丝受拉，内混凝土芯和钢瓶受压。管道的顶部和底部的载荷状态与管道的弹力线处的载荷状态相反，但变形协调一致。此外，测试结果表明，基于PPP-BOTDA的分布式光纤传感器不仅可以像FBG点光纤传感器一样准确监测PCCP在外部负载下的实时负载响应，而且可以获得动态和连续的应变分布管道圆周截面的角度。这项研究已经确定了PCCPs的外部载荷与变形的关系，相互作用和应变分布的关系。