基于分布式光纤传感技术的铁路路基岩溶土洞塌陷监测

Monitoring of collapse of karst cavern under railway subgrade based on distributed optical fiber sensing technology

岩溶土洞塌陷是铁路路基最为严重的破坏形式,具有隐伏性强、空间分布广的特点。鉴于常规监测与检测方法难以满足路基岩溶土洞塌陷分布式监测要求,本文提出采用分布式光纤布里渊传感技术对土洞塌陷进行识别和定位。在应用该技术时,采用纤维增强树脂封装保护用于土洞塌陷监测的分布式光纤布里渊传感器,并利用绝对温度补偿方法剔除环境温度对塌陷应变测试的影响。路基岩溶土洞塌陷模型试验结果表明:绝对温度补偿技术可以有效剔除环境温度变化引入的塌陷应变误差,基于分布式塌陷应变信息可以有效识别和定位土洞塌陷,塌陷应变测试结果与岩溶土洞塌陷实际情况吻合。

Karst cavern collapse is the most serious failure mode of railway subgrade with strong insidious and wide spatial distribution. Common monitoring and inspection methods cannot meet the requirement of distributed monitoring,so distributed Brillouin Optical Fiber sensing technology was put forward for the collapse location and identification. Collapse monitoring sensor was packaged by the fiber reinforced polymer,and absolute temperature compensation was developed to eliminate the effect of environmental temperature on collapse strain measurement.Experimental results show that absolute temperature can effectively eliminate the strain error induced by the temperature influence,the collapse strain was agreed with the real condition of cavern collapse based on the distributed collapse strain from cavern collapse identification and location.