FBG传感器在量测围岩内部位移中的应用

 光纤光栅(FBG)传感器利用波长调制传感信号，因而量测信号不受光源起伏、光纤弯曲损耗、连接损耗和探测器老化等因素的影响，可以广泛应用于量测应变、温度、应力、位移等参数。结合新奥法隧道施工中位移监测的要求，介绍光纤光栅传感器的原理及其在隧道围岩内部位移量测中的应用。与其他量测方法比较，利用光纤光栅传感器量测围岩内部位移具有仪器构造简单、安装量测方便、量测数据精确等优点，是一种非常实用的量测方法。量测数据验证隧道围岩变形的基本规律：不同位置的围岩其松弛变形不同，离开挖面越近的围岩，其松弛变形越大，离开挖面越远的围岩，相应的松弛变形越小；围岩的完整程度对围岩内部位移的影响很大。

APPLICATION OF FBG SENSOR TO INTERNAL DISPLACEMENT MONITORING OF SURROUDING ROCK

The most important advantage of fiber Bragg granting(FBG) sensor is the wavelength-encoded information given by the Bragg grating，since the signal from Fiber Bragg granting sensor immunes to power fluctuations，optical fiber bend loss，optical fiber connection loss along the optical path. Fiber Bragg granting sensor can be used to measure many different parameters including strain，temperature，stress，displacement，etc. Based on displacement monitoring of new Austrian tunneling method(NATM)，this paper describes the principle and application of fiber Bragg grating sensor in surrounding rock internal displacement monitoring. Comparing with other methods，this measurement method is an excellent and practical method which has the advantages such as simple instrument architecture，easy installation，convenient measurement，accurate measured data. The FBG sensor has been applied to the practical engineering. The measured data proved that：the relaxation deformation of surrounding rock will change along with the change of location，the relaxation deformation descends slowly when the depth from excavated surface increases；the integrity level of surrounding rock has great effects on its internal displacement.