Abstract The results obtained during a pile test are dependent on a number of factors. However, conventional monitoring systems like vibrating wire strain gauges and the extensometers can only measure the variations of strain and displacement at discrete locations at which they are installed in a pile. In order to identify the behavior of Continuous Flight Auger (CFA) pile, the distributed fiber optic monitoring system and three-dimensional laser scanning collected the strain and point clouds data during the pile test with conventional vibrating wire strain gauges, extensometers. Based on the Brillouin Optical Time Domain Reflectometry (BOTDR) fiber optic strain profile, the profiles of axial load, skin friction, displacement can be obtained. The fiber optic monitoring system was compared with conventional systems, and it was found that the ability to measure the full strain profiles is highly advantageous in determining the performance of the pile and in detecting the behavior of CFA pile. The displacement of the pile was measured by the LVDT at the top of the pile and the results were compared with the laser scanning results. In this study, the negative skin friction was detected by BOTDR fiber optic strain profile near the top of the CFA pile. It was not able to define the reason of the negative skin friction from the other monitoring systems but the laser scanning results show that the ground movement due to the pull-out force of the anchor pile affects the negative skin friction. Although laser scanning is not able to measure the real-time data during the pile test, the extensive information can be taken into account by the monitored data from three-dimensional laser scanning.

中文翻译：

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使用三维激光扫描和分布式光纤传感器监测 CFA 桩测试

摘要 在桩试验期间获得的结果取决于许多因素。然而，传统的监测系统，如振弦式应变计和引伸计，只能测量安装在桩中的离散位置的应变和位移变化。为了识别连续飞行螺旋钻（CFA）桩的行为，分布式光纤监测系统和三维激光扫描使用常规振弦应变计、引伸计收集桩测试过程中的应变和点云数据。基于布里渊光时域反射计 (BOTDR) 光纤应变剖面，可以获得轴向载荷、皮肤摩擦、位移的剖面。将光纤监控系统与传统系统进行比较，并且发现测量全应变曲线的能力在确定桩的性能和检测 CFA 桩的行为方面非常有利。通过桩顶LVDT测量桩身位移，并与激光扫描结果进行对比。在这项研究中，负表面摩擦是通过 CFA 桩顶部附近的 BOTDR 光纤应变剖面检测到的。其他监测系统无法确定负表面摩擦的原因，但激光扫描结果表明，由于锚桩拉拔力引起的地面运动会影响负表面摩擦。虽然激光扫描无法测量桩测试过程中的实时数据，