塑料光纤在渗透稳定性监测中的应用方法研究

针对土石坝、堤防和堰塞坝等结构无法通过预埋设备实现渗透稳定性监测的问题,提出一种使用塑料光纤监测渗流泥沙含量的方法,即考虑不同的光波透射距离及不同泥沙含量对光能损耗的影响,间接实现结构渗透稳定性的监测。使用透射距离为2.3 mm的两种实验装置测量0~800 NTU的泥沙悬浊液,研究光能损耗与悬浊液浊度、透射距离的关系。结果表明,光能损耗幅度与泥沙悬浊液浊度呈线性变化,损耗幅度随浊度的增大而增大;光能损耗速度随透射距离的增加而增加.2、3 mm透射距离装置的光能损耗速度分别为2.38、2.75μW/100 NTU。试验验证了光能在泥沙悬浊液中的损耗规律基本符合郎伯-比尔定律,并且透射距离影响装置的监测性能,证明运用塑料光纤监测渗流泥沙含量,从而实现结构渗透稳定性监测是可行的。

Research on A pplication Method of Plastic Optical Fiber in Monitoring Seepage Stability

The traditional monitoring facilities can’t be embedded in the structure to monitor the seepage stability,such as the earth-rock dam,levee and landslide dam.A new method to monitor the sediment content of seepage by plastic optical fiber is presented,which indirectly monitor the seepage stability.The monitoring capability of plastic optical fiber in monitoring the turbidity of seepage,which considering the difference of loss amplitude of light energy under different transmission distance or different sediment content.Two kinds of experimental devices with transmission distance of 2 mm and 3 mm are used to measure the sediment turbid liquor during 0-800 NTU.Then the relationships between the loss of light energy loss and turbidity,the light energy loss and transmission distanced are analyzed.The results demonstrate that the amplitude of light energy loss increases linearly with the increase of turbidity.Moreover,the speed of light energy loss increase with the increase of transmission distance,that the loss rate of the facility is 2.38 μW/100 NTU while the loss rate transmission is 2 mm and the loss rate of the facility is 2.75μW/100 NTU while the loss rate transmission is 3 mm.The loss law of light energy loss in sediment suspension accords with the Lambert Beer law is proved by experiment,and the monitoring properties of the facility is affected by the transmission distance,that using the plastic optical fiber to monitor the content of seepage sediment,which indirectly realize the structural seepage stability.