面向边坡滑移的剪切位移传感装置

Optical Fiber Bragg Grating Sensor Using Cantilever Beam of Qual Strength for Slope Sliding Displacement Monitoring

基于光纤布喇格光栅传感监测原理,设计了一种用于岩土滑坡监测的剪切位移传感装置.在等强度悬臂梁上粘贴光栅构成位移传感器,位移传感器被嵌入Φ50的聚氯乙烯树脂管中,Φ50聚氯乙烯树脂管外套Φ70聚氯乙烯树脂管,在两管之间浇筑1:1的砂浆.通过室内模拟剪切测试,该装置对剪切位移测量为30mm,初测精度为0.5mm,其对30mm位移传感转变成光栅波长变化量为1 200pm.该装置灵敏度高、稳定性好、测量范围大、线性好、结构简单,可用于滑坡以及野外岩土结构工程等进行长期有效的监测.

A shear displacement sensoring device for monitoring rock sliding based on the principle of optical fiber Bragg grating. The displacement sensor was designed by attaching the fiber grating to equal strength cantilevers. Then the sensor was embedded inside a qφ50 polyvinyl chloride （PVC） tube. Three test models were made using φ75 PVC tube with the φ50 PVC tube mentioned before in it. Cement mortar was grouted into the gap between the φ50 and φ75 PVC tubes as ratio at 1 ： 1. Indoor shearing tests on the models were carried out. The curve of the relationship between the sliding distance and the grating wavelength shift was also measured. Results show that the sensitivity of this sensor is 0.5 mm and the maximal sliding distance could reach 30 mm while the grating wavelength could shift up to 1200 pm,of which indicates that the sensor could be well applied into sliding displacement measurement which needs a very high sensitivity. It is proved that the features of the fiber Bragg grating （FBG） sensor we designed are more sensitive and reliable, better anti-interference ability and larger measurement range. The structure of the sensor is simple, and it also can realize remote, real-time monitoring. Thus, the sensor can be used for landslide early warning monitoring.