一种准分布式内加热刚玉管FBG渗流速率监测方法

A Quasi-distributed Seepage Velocity Monitoring Method Using FBG Embedded in Internal Heated Alundum Tube

岩土体中的渗流是引发各种地质灾害的重要因素。针对现有渗流监测技术的不足,提出了一种基于光纤布拉格光栅FBG的准分布式内加热刚玉管FBG渗流监测方法;介绍了该方法的原理;发明了一种新型内加热刚玉管渗流传感器;推导出了温度特征值与渗流速率之间的关系,并通过砂性土室内模型试验对此关系进行了率定。试验结果表明：（1）本方法对砂性土中渗流速率进行监测是可行的;（2）利用刚玉管封装的新型传感器具有很好的监测性能;（3）在给定加热功率条件下,一定渗流速率范围内,温度特征值与渗流速率间存在线性关系,渗流速率越大,温度特征值越小;（4）一定加热功率条件下的渗流速率监测存在相应的测试量程,提高给定加热功率可提高监测量程。

Seepage in the rock and soil is an important factor causing various geological disasters.A new quasi-distributed seepage velocity monitoring method with fiber Bragg gratings（FBGs）embedded within an internal heated alundum tube is proposed to overcome the shortcomings of the existing seepage monitoring technology.The theory of the monitoring method is described,and a new seepage monitoring sensorwith an internal heated alundumtube is invented.The relationship between the characteristic temperature value（ΔTt）and the seepage velocity（v）is deduced,and a laboratory test is conducted in sandy soil to calibrate the afore-mentioned relationship.The following conclusions are drawn from the test：（1）It is feasible to monitor seepage velocity by using the FBG sensor;（2）The newly-invented sensor shows good performance;（3）Under a given heating power,there is a linear relationship betweenΔTtand vin a certain range of seepage velocity;the larger the seepage velocityis,the smaller the characteristic temperature value will be;（4）The measurement range of seepage velocity is conditioned by the heating power;the measurement range can be increased by increasing the heating power.