光纤光栅传感技术在PHC管桩水平载荷试验中的应用

光纤Bragg光栅(FBG)传感技术在工程测试方面优势显著，如何合理应用该项技术实施PHC管桩的荷载试验，难度较大，相关研究工作与实践经验较少。基于FBG工作原理与硬件特性的分析，结合PHC管桩成型与现场施工的工艺特点，利用PHC管桩水平承载力载荷试验的实践验证，研究FBG传感器合理应用于PHC管桩的埋设方案与施工技术。结果表明：按笔者提出的预设方案与施工技术，在PHC管桩采用锤击和静压2种成桩工艺时，FBG传感器的成活率可达100%；FBG传感器获得的PHC管桩应变与应力监测数据，比传统电阻应变式传感器更具优越性；实测数据与理论计算的对比分析证实，《建筑桩基技术规范》(JGJ 94—2008)中有关水平承载力的计算方法能够较好地反映桩身受力的实际情况。

APPLICATION OF FIBER BRAGG GRATING SENSOR TO LATERAL LOAD TESTS OF PHC PIPE PILES

Fiber Bragg grating(FBG) sensor has been widely applied to different engineering tests due to its superiority of basic principle and usability. However，it is difficult to adopt FBG sensor on the load tests of PHC pipe pile because the relative research results and practical knowledge in the case of PHC pipe pile are still lack. Based on the analysis of operational principle and hardware features of FBG sensor，embedding methods of FBG sensors for PHC pipe pile through one field test of lateral loading on this kind of pile are carefully investigated. During the embedding process，the specials acquirements within product and piling of PHC pipe pile are adequately considered. The practical results show that the survival ratio of FBG sensors could reach 100% according to the embedding scheme and technique proposed by the author，while the PHC pipe pile is operated by the both ways of hammering and static pressure. Meanwhile，the test data of lateral load of PHC pipe pile by means of FBG sensors reveal their qualities of precision，zero drift and stability are better than those obtained by traditional electric resistance wire strain gauges. The further comparative analysis of different internal force distributions in the body of PHC pipe pile，which are respectively received by the field test and theoretical computation method proposed by Technical code for building pile foundation(JGJ 94——2008)，discloses that the computation method in the code could reflect the practical situation of internal force behaviours of pile under lateral loading. The practical results and comprehensive analysis reported by authors indicate that FBG sensor is a better suitable kind of technique to monitor internal strain behaviors of precast concrete piles under lateral loads.