微型FBG应变传感器在大坝模型实验中的应用

Application of Small FBG Strain Sensors in Dam Model Experiment

为了对大坝的地震安全性能进行准确可行的评价,在大坝模型实验中应用了自行开发的微型光纤光栅(fiber bragg grating,简称FBG)应变传感器。通过分析FBG应变传感器在每级地震作用下产生的残余应变、峰值应变,得到大坝的内部变形和裂缝发展情况,进而对大坝的地震安全性能进行评价。实验结果表明,该传感器能够及时准确地监测大坝模型在地震荷载作用下内部混凝土变形以及开裂情况,对结构的损伤进行识别和预警。通过对比有筋坝段和无筋坝段的变形和开裂情况得知,在模型的薄弱位置布设钢筋可以有效抑制裂缝的产生以及发展,提高大坝的抗震性能。

In order to get accurate and feasible seismic safety evaluation of a real dam,a self-developed miniature fiber bragg grating(FBG) strain sensor is used in this dam model experiment.By analyzing residual strain and peak strain produced by miniature FBG sensor in different magnitude,internal deformation and cracks of the dam model can be monitored,then seismic ability of the dam can be evaluated.The results of the experiment show that FBG sensor has high sensitivity and good anti-interference ability.It can monitor internal deformation and cracks of the dam model timely and accurately,then identify and warn structural damages.Through comparing concrete deformation and cracks produced by reinforced dam and unreinforced dam,it shows that steel bars embedded in the dam's weak position can restrain creation and development of cracks effectively and improve the anti-seismic capacity of dam significantly.The results of the experiment provide important basis for engineering design and the evaluation of dam anti-seismic ability.