光纤传感技术在冶勒水电站大坝变形监测中的应用

Application of optical fiber sensing technique to the deformation monitoring of Yele dam

用传统传感器检测混凝土大坝的裂缝在全面收集其重要实况信息方面尚有一定局限性,分布式传感光纤可以有效解决这一难题。基于"瑞利散射一微弯损耗"原理机制,当混凝土出现裂缝时,埋设于其中的传感光纤受到拉剪作用,引起光纤产生微弯,并引发光强损耗,通过光损耗变化大小、分布状态和距离,从而迅速检测出裂缝的位置、宽度等。冶勒水电站大坝混凝土防渗墙基座变形监测中应用了分布式光纤传感技术,效果良好。

Many a time, traditional sensor can not meet requirement in detecting internal cracks in concrete dam, however, distributed sensing fiber can solve such problem effectively. Based on Rayleigh Scattering and microbending loss theory, when cracks occur in the concrete, sensing fiber embedded in concrete bears pulling-shearing force and micorbending is produced on fiber, thus high optical loss is produced. Therefore, sensing fiber can detect position and width of crack after optical loss and its relative position is determined. Yele Project, in which the distributed optical fiber sensing technique was used in concrete foundation of impermeable wall to monitor its deformation, is also introduced as an example.