基于光纤光栅的冻土含冰量监测可行性试验研究

含冰量是冻土研究的一项重要参数。针对现有含冰量测量的局限性,提出了一种基于光纤布拉格光栅（FBG）的冻土含冰量监测方法。结合冻土温度场,应用内加热FBG刚玉管传感器,通过室内标定试验验证该方法的可行性;基于传统导热系数模型推导出温度特征值与含冰量之间相应函数模型,并应用试验数据进行验证。研究结果表明：试验所得温度特征值随冻土含冰量增加而减小,可以通过该规律初步判断含冰量范围;在温度特性值与含冰量数值关系的拟合中,指数函数模型与本次试验数据拟合度最高,含冰量测量误差小于2%,在可接受范围内;本方法实现冻土含冰量监测具有可行性。

Feasibility study on FBG-based monitoring method for ice content in frozen soil

The ice content is an important parameter in frozen soil research. Aiming at the limitation of the existing ice content measurement, a method based on fiber Bragg grating (FBG) for monitoring the ice content in frozen soil is proposed. Based on the temperature field of frozen soil, a series of indoor calibration tests are performed using the FBG corundum tube sensor with internal heating. The corresponding function model between characteristic value of temperature and ice content is deduced and verified using the experimental data. The results show that the proposed method is feasible to monitor the ice content in frozen soil, the characteristic value of temperature decreases with the increase of ice content in frozen soil, and the approximate range of ice content can be preliminarily judged by this law. In the fitting of the function model, the exponential function model has the highest fitting degree with the experimental data, and the measurement error of ice content is less than 2% within the acceptable range.