光纤光栅传感技术在洞室围岩变形监测中的应用

Application of fiber grating sensing technology in deformation monitoring of cavern surrounding rock

光纤光栅传感器利用波长调制传递信号,具有测量精度高、抗干扰强、传输距离远、可连续测量等特点,在桥梁结构健康监测、火灾报警等领域已得到广泛应用,但在洞室围岩变形(应变)监测中应用较少。通过对光纤光栅传感器和多点变位计在围岩变形(应变)监测中的应用对比,发现光纤光栅传感器易受施工爆破振动影响,且随着运行时间的增长,有效测点数逐渐减少。为此针对性地提出了有效测点判别和异常测值内插处理的新方法,经处理,光纤光栅传感器能较好地反映洞室围岩变形(应变)变化规律,且与多点变位计测值在空间分布和时间序列上一致性较好,为洞室围岩变形(应变)监测提供了新方法。

Fiber grating sensor can transmit signal by wavelength modulation and has the characteristics of high measurement accuracy, high anti-interference ability, long transmission distance, continuous measurement and so on. It has been widely used in bridge structure safety monitoring, fire alarm and other fields. But it is less used in deformation(strain) monitoring of caverns surrounding rock. By comparing the application of fiber grating sensor and multi-point displacement meter in deformation(strain) monitoring of surrounding rock, it is found that fiber grating sensor is vulnerable to blasting vibration in construction, and the number of effective measurements decreases gradually with the increase of running time. Therefore, a new method for discriminating effective measurement point and interpolation abnormal measurement value was put forward. After treatment, the fiber grating sensor can better reflect the variation law of cavern surrounding rock deformation(strain), and was in good agreement with the measured values of multi-point displacement in spatial distribution and time series, which provided a new method for deformation(strain) monitoring of cavern surrounding rock.