土体温度光纤精细化监测室内试验研究

传统温度传感器在测量地下土体温度时存在耐腐蚀性差、易受电磁干扰、易被破坏等不足,难以准确和全面地掌握土体温度的长期变化。通过对比分析常用的几种分布式光纤测温技术,提出采用光频域反射技术来监测地下土体温度。根据光频域反射技术高精度和高空间分辨率的特征,给出了土体温度光纤精细化监测的布设方案和监测数据的分析思路。为了验证光频域反射技术在土体温度监测方面的优势和可行性,开展了土体温度室内模拟监测试验,设计出了一套土体温度光纤精细化测温装置,采用光频域反射技术对不同容器内的土体和水体温度进行监测,掌握了土体和水体温度的变化情况,并与传统测温方法进行了对比,结果表明,光纤测得的土体温度结果与传统方法得到的结果基本一致,但光纤测温可以实现分布式测量,相对于传统方法优势显著,对于土体温度精细化测量而言,取得了良好的成果。

Experimental study on underground soil temperature monitoring based on OFDR

The traditional temperature sensor has some shortcomings in measuring the temperature of underground soil,such as poor corrosion resistance,vulnerable to electromagnetic interference and easy to be damaged. It is difficult to accurately and comprehensively obtain the long-term variation of soil temperature. In this paper,several distributed optical fiber temperature measurement techniques are compared and analyzed. It is proposed to use optical frequency domain reflection technology to monitor the temperature of underground soil. According to the characteristics of high precision and high spatial resolution of optical frequency domain reflection technology,the detailed monitoring scheme of optic fiber and the analysis of monitoring data are presented. In order to verify the advantages and feasibility of optical frequency domain reflectance technology in soil temperature monitoring,an indoor simulation monitoring test of soil temperature is carried out,and a set of fine temperature measurement device of soil temperature using optic fiber is designed. The optical frequency domain reflectance technology is used to monitor the temperature of soil and water in different containers. It shows that the result of optic fiber is basically consistent with the result obtained from the traditional method,but the distributed measurement can be realized by the optical fiber temperature measurement. It is remarkable compared with the traditional method. The good result of the soil temperature measurement is achieved.