光纤Bragg光栅应变测试技术在大型振动台模型试验中应用

摘要

基于可液化地基上三拱立柱式地铁地下车站结构非破坏性振动台模型试验，用光纤Bragg光栅测试模型结构中柱镀锌钢丝应变时程，用应变片测试对应位置处微粒混凝土应变时程；运用Mann-Whitney U非参数检验方法，定量分析镀锌钢丝与微粒混凝土的协同工作关系。结果表明，模型结构在地震动作用下，处于弹性或轻微损伤工作阶段；不同地震动作用时，模型结构中柱顶部及底部镀锌钢丝应变测试样本与微粒混凝土应变测试样本非参数检验系数P均大于0．05，两者无显著性差异；对中柱中部，光纤Bragg光栅测试的应变形态显著优于应变片测试结果。对电磁干扰较大、信号较弱的测试部位或小尺寸基体材料，采用光纤光栅传感测试技术更适合。%Based on the non-destructive shaking table model test of a three-arch type underground station structure of subway on a liquefiable foundation,the strain responses of galvanized steel wires in the center pillar of the model were measured with optical fiber Bragg grating sensing technology and the strain responses of microconcrete at the corresponding positions were measured with strain gauges.The synergy relations of galvanizing steel wires and microconcrete were analyzed quantitatively with Mann-Whitney U non-parameter detection method.The results showed that the model structure is in an elastic or minor damage working stage under the action of ground motion;the inspection coefficient P values obtained with Mann-Whitney U non-parameter detection method at the top and bottom of the center pillar of the model are all larger than 0.05 under different ground motions;at the middle part of the center pillar ,the strains obtained with fiber Bragg grating measuring technique are obviously better than those with strain gauges;under larger electromagnetic interferences,for the positions where there exist relatively weak signals or basis materials of small sizes,the fiber Bragg grating sensing technique is more applicable.