新型自温补FBG锚杆测力计研制优化及应用

Optimization design of a novel FBG anchor dynamometer with temperature self-compensation and its application

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△λ_B与外界压力F之间的对应关系为△λ_B=9.4735·Fo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 AM of pressure sensitivity FBG and external load F is calculated to be AM=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.