基于光纤Bragg光栅应变传感器的量测锚杆拉力研究

由于被锚固结构自身的风化作用和锚杆自身的受力,蠕动变形等会改变锚杆的受力状态。为了实时反映锚杆的受力状态,将光纤Bragg光栅应变传感器通过引脚沿轴向焊接在锚杆的杆体上。由于锚杆杆体受力带动光纤Bragg光栅应变传感器引脚间距发生变化,使得应变传感器内的光纤Bragg光栅中心波长发生移位。通过对光纤Bragg光栅中心波长移位量的测量,可以实现对锚杆轴向拉力的在线监测。锚杆拉力试验表明:拉力灵敏度为6.5 pm/kN,线性度为1.78%FS。

Research on tension of anchor bolt based on fiber Bragg grating strain sensor

The stress state of anchor bolt changes because of the weathering of anchoring structure,the stress of the bolt itself,the creep deformation will change stress state of bolt.In order to real-time reflect stress state of stress state of anchor bolt,the fiber Bragg grating strain sensor is welded to the bolt body by pin in an axial direction.The pin distance of fiber Bragg grating strain sensor changes by the stress of the bolt,which makes the fiber Bragg grating center wavelength occur shift inside strain sensor.Through displacement measurement of the fiber Bragg grating center wavelength,on-line monitoring of anchor bolt＇s axial tension can be realized.Tension tests of anchor bolt indicate that the sensitivity is 6.5 pm/kN,and the nonlinearity error is 1.78 ％ FS.