光纤光栅应变检测技术在预制桩中的应用研究

Research on application of fiber grating strain measurement technique in precast piles

光纤光栅表面式GFRP桩基应变计具有分布式和长距离检测等特点,并且此种桩基应变计易埋入到成型的预制工程构件中,在桩身内力测试中具有独特的优势。介绍了在软土地区预制桩检测中采用布里渊光时域反射技术(BOTDR)的传感原理及GFRP桩基应变计的植入工艺,根据测试结果对比分析桩身内力、桩周摩阻力及桩端阻力,更加全面地了解地层特性及预制桩承载特性,为设计参数的优化提供可靠依据。

Fiber grating surface GFRP pile strain gauge has the characteristics of distributed and long-distance detection,and this kind of pile strain gauge is easy to be embedded in the formed prefabricated engineering components,and has a unique advantage in the internal force testing of piles.This paper introduces the sensing principle of Brillouin optical time domain reflectometry(BOTDR)technology and the implantation process of GFRP pile foundation strain gauge in the detection of precast piles in soft soil areas.Based on the test results,the internal force of piles,the friction resistance around piles and the resistance at the end of piles are compared and analyzed,so as to have a more comprehensive understanding of the formation characteristics and the bearing characteristics of precast piles,and provide a reliable basis for the optimization of design parameters.