针对现有锚杆端部载荷监测仪器无法满足岩土工程长期监测及数据远距离传输的现状,基于光纤光栅轴向应变特性,提出一种结构简单、自带温补并适用于工程测量的新型FBG 锚杆测力计.通过SolidWorks 2012 有限元仿真软件,分析锚杆测力计在外界压力下的轴向应变分布,进一步优化设计传感器内部结构,提高传感器的应变传递系数.理论计算得该锚杆测力计压力敏感光栅中心波长的变化量ΔλB与外界压力F 之间的对应关系为ΔλB=9.4735·F.性能实验数据表明该传感器线性度大于0.99,压力测量分辨率为0.093 kN,压力敏感系数K 为10.7 pm/kN.将该FBG 锚杆测力计应用于某煤矿巷道,现场测试数据证实该传感器可以实时的监测围岩压力变化,满足井下复杂测量坏境的需求,实用性较强.
Because existing anchor end load testing instruments can not achieve long-term geotechnical engineering monitoring and long- distance data transmission, a novel FBG anchor dynamometer with simple mechanical structure and temperature selfcompensation suitable for engineering monitoring is proposed based on the axial strain characteristic of fiber Bragg grating. In order to improve strain transfer coefficient of this novel FBG sensor, its internal structure is analyzed by Solidworks 2012 finite element simulation software and further optimized based on axial strain distributions of this FBG anchor dynamometer. The relationship between center wavelength shift ΔλB of pressure sensitivity FBG and external load F is calculated to be ΔλB=9.4735·F theoretically. It is shown by performance experiment data that linearity of this sensor is larger than 0.99, its pressure measurement resolution is 0.093 kN and sensitivity coefficient K is 10.7 pm/kN. Coal mine tunnel pre-stressed anchor experiment data confirm that this sensor can achieve real-time surrounding rock pressure measurement, and that it well matches the measurement requirements under complex situation and has certain practical value.
[1] 赵一鸣. 煤矿巷道树脂锚固体力学行为及锚杆杆体承载特性研究[D]. 徐州: 中国矿业大学, 2012. Zhao Yiming. Study on mechanical bebavior of epoxy bonded bolt system and bolt bearing characteristic in coal mine roadway[D]. Xuzhou: China University of Mining and Technology, 2012.
[2] 黎剑华, 张鸿, 刘优平, 等. 光纤Bragg光栅在公路软基沉降监测中的 应用[J]. 中南大学学报: 自然科学版, 2011, 42(5): 1442-1446. Li Jianhua, Zhang Hong, Liu Youping, et al. Fiber Bragg grating monitoring technology applied in soft ground settlement of high way[J]. Journal of Central South University: Science and Technology, 2011, 42 (5): 1442-1446.
[3] 刘胜春, 张顶立, 黄俊, 等. 大型盾构隧道结构健康监测系统设计研究[J]. 地下空间与工程学报. 2011, 7(4): 741-748. Liu Shengchun, Zhang Dingli, Huang Jun, et al. Research and design on structural health monitoring system for large-scale shield tunnel[J]. Chinese Journal of Underground Space and Engineering, 2011, 7(4): 741-748.
[4] 段杭, 任大春, 王宗魁, 等. 光纤Bragg光栅温度传感器在三峡大坝坝 前水温监测中的应用[J]. 长江科学院院报, 2010, 27(9): 25-28. Duan Hang, Ren Dachun, Wang Zongkui, et al. Application of FBG temperature sensors in water temperature monitoring for three gorges dam[J]. Journal of Yangtze River Scientific Research Institute, 2010, 27 (9): 25-28.
[5] Zhang X S, Ning C X. Application of fiber Bragg grating sensors on monitoring of cables'tension[C]//Proceedings of the Eighth International Conference on Electronic Measurement and Instruments. ICEMI, 2007: 4-232-4-235.
[6] Kerrouche A, Boyle W J O, Sun T, et al. Strain measurement using embedded fiber Bragg grating sensors inside an anchored carbon fiber polymer reinforcement prestressing rod for structural monitoring[J]. IEEE Sensors Journal, 2009, 9(11): 1456-1450.
[7] 隋海波, 施斌, 张丹. 基于BOTDR的锚杆拉拔试验研究[J]. 岩土工程 学报, 2008, 30(5): 755-759. Sui Haibo, Shi Bin, Zhang Dan. BOTDR- based pull- out tests on anchor bolts[J]. Chinese Journal of Geotechnical Engineering, 2008, 30 (5): 755-759.
[8] 柴敬, 赵文华, 李毅, 等. 光纤光栅检测的锚杆拉拔实验研究[J]. 中国 矿业大学学报, 2012, 41(5): 719-723. Chai Jing, Zhao Wenhua, Li Yi, et al. Pull out tests of fiber Bragg grating sensor fitted bolts[J]. Journal of China University of Mining and Technology, 2012, 41(5): 719-723.
[9] 李毅, 柴敬, 邱标. 带有温度补偿的光纤光栅锚杆测力计设计[J]. 煤炭 科学技术, 2009, 37(2): 90-93. Li Yi, Chai Jing, Qiu Biao. Design on optical fiber and optical grating bolt dynamometer with temperature compensation[J]. Coal Science and Technology, 2009, 37(2): 90-93.
[10] 裘祖荣. 精密机械设计基础[M]. 北京: 机械工业出版社, 2007. Qiu Zurong. Elementary precision machinery design[M]. Beijing: China Machine Press, 2007.
[11] 廖延彪. 光纤光学——原理与应用[M]. 北京: 清华大学出版社, 2010. Liao Yanbiao. Fiber optics: Principles and applications[M]. Beijing: Tsinghua University Press, 2010.
[12] Dong X, Wu C Y. Study on the application of FBG monitoring on roof falling of mine based on model experiment[C]. Management and Service Science 2010 International Conference, Wuhan, August 24- 26, 2010.
