作者：吴冰1, 朱鸿鹄*,1,2, 曹鼎峰3, 魏广庆4, 施斌1
1. 南京大学地球科学与工程学院,江苏 南京 210023;
2. 冻土工程国家重点实验室,甘肃 兰州 730000;
3. 中山大学土木工程学院,广东 广州 519082;
4. 苏州南智传感科技有限公司,江苏 苏州 215123
摘要：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。
关键词： 冻土, 含冰量, FBG, 函数模型
基金资助: 国家重点研发计划项目（2018YFC1505104）; 国家自然科学基金优秀青年基金项目（41722209）; 冻土工程国家重点实验室开放基金项目（SKLFSE201814）
图1 AH-FBG探针结构图
图3 (a) 含冰量参考值-温度特征值关系曲线；(b) 监测结果误差分析
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Feasibility study on FBG-based monitoring method for ice content in frozen soil
WU Bing1, ZHU Hong-hu1,2, CAO Ding-feng3, WEI Guang-qing4, SHI Bin1
1. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China;
2. State Key Laboratory of Frozen Soil Engineering, Lanzhou 730000, China;
3. School of Civil Engineering, Sun Yat-Sen University, Guangzhou 519082, China;
4. Nanzee Sensing Technology Co., Ltd., Suzhou 215123, China
Abstract：
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.
Key words： frozen soil ice content FBG function model