松散地层深部沉降变形的光纤Bragg光栅监测

Settlement deformation detecting in deep unconsolidated soil layer by fiber Bragg grating sensing technology

为了监测松散含水地层沉降变形，提出了一种在预设钻孔中埋入光纤Bragg光栅传感器网络系统的监测方法．根据光纤Bragg光栅传感原理和矿井地层情况，设计并实现了一个由18个光纤光栅组成的具有特色的光纤Bragg光栅波分复用／空分复用混合阵列，研究了光纤Bragg光栅传感器应变传递规律，通过监测得出了风井松散层应变变化情况，在146～149m的砂砾层和167～176m的黏土层处应变最大，截至2008—05—01最大应变变化量为121．68με。工程实践表明，光纤光栅传感器监测正常，系统稳定，光纤光栅作为应力应变检测使用安全可靠。

In order to detect the settlement deformation of extra thick hydrous unconsolidated soil layer in the Quaternary system during the course of the mining, the fiber Bragg grating （FBG） network system was installed in the preformed borehote, and the monitoring method was proposed. According to the FBG sensing principle and the geology conditions of the coal mine, a distinctive FBG array composed of 18 FBGs based on wavelength division multiplexing （WDM） /spatial division multiplexing （SDM） was designed and implemented. The strain transfer principle of the FBG sensor was researched. The strain distribution of different unconsolidated soil layer was obtained through monitoring, the unconsolidated soil layer has the maximum value in the depth of 146-149 m and 167 176 m, the maximum strain change is 121.68με up to 2008 -05 -01. Engineering practice shows that these FBG sensors can work normally, and the monitoring system works stably, it is safe and reliable to use FBG system for the strain detecting of the unconsolidated soil layer.