基于FBG-BOTDA联合感测的岩层运动试验研究

1.西安科技大学 能源学院,陕西 西安 710054; 2.教育部 西部矿井开采及灾害防治重点实验室,陕西 西安 710054

模拟试验; 温度补偿; FBG-BOTDA联合感测; 岩层运动

Strata movement testing based on FBG-BOTDA combined sensing technology in similar model
CHAI Jing1,2,SUN Ya-yun1,QIAN Yun-yun1,SONG Jun1,MA Wei-chao1,LI Yi1,2

(1.College of Energy Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Key Laboratory of Western Mine Exploration and Hazard Prevention,Ministry of Education,Xi'an 710054,China)

simulation test; temperature compensation; FBG-BOTDA combined sensing; strata movement

DOI: 10.13800/j.cnki.xakjdxxb.2016.0101

备注

为研究采场上覆岩层运动过程中的应力应变,将准分布式布拉格光纤光栅技术(FBG)和基于脉冲预泵浦布里渊光时域分析的分布式光纤传感技术(PPP-BOTDA)联合应用于相似材料模型试验的测试中。在2 m平面应力模型内埋设2根分布式传感光纤和2个光纤光栅应变传感器,模型尺寸2 000 mm×180 mm×1 700 mm,几何相似比1:250,测试主关键层由弯曲下沉发育至断裂的变形运动过程。试果表明,2煤开采过程中分布式传感光纤应变曲线体现了岩层的连续变形下沉,曲线中间位置出现应力集中; 3煤开采过程中分布式传感光纤应变曲线体现了发生断裂的岩层运动,断裂后的岩层应力得到释放; 连续变形下沉的岩层FBG传感器应变曲线呈宽缓峰状,应变值达到4 367.48 με; 断裂的岩层曲线呈尖峰状,最大应变值达到4 892.82 με.实现了模型试验中主关键层由连续体转变为半连续体过程的实时监测。

For the study of stress and strain in the process of mining overburden movement,the quasi-distributed fiber Bragg grating(FBG)and the brillouin scattering optical time-domain analysis based on pre-pumping technique(PPP-BOTDA)are applied to similar material model test together.Two sensing fibers and two fiber Bragg grating strain sensors were embedded in the 2 m plane stress physical model,the model size 2 000 mm×180 mm×1 700 mm and geometric similarity ratio 1:250,for analyzing the stress and strain of the main key strata from the process of flexural settlement development to fracture.The results of the study show that 2# coal mining of horizontal strain optical fiber's curve reflects the continuous deformation of the strata in the middle position of the stress concentration.In the process of 3# coal seam mining,horizontal strain optical fiber's curve shows that a stress release phenomenon occurred while the model was stable.FBG sensor strain curves shows a broad peak while the continuous deformation of the layered rock fissure appears,and the maximum strain value is 4 367.48 με.The fracture type of the layered rock is failure,and the curve is a spike like,the maximum strain value to 4 892.82 με.This experiment realizes the real-time monitoring of key strata,which the whole and the part of the process of continuous changing to a semi continuous.