基于分布式光纤测温技术的堤坝渗漏监测

渠道堤坝普遍存在渗透变形及渗漏破坏等工程问题,传统大坝及岸堤安全监测技术测点分散、容易漏测。在介绍分布式光纤测温技术原理的基础上,通过室内试验和现场原型试验,开展了分布式光纤测温技术方法比选、测量精度和稳定性分析、渗漏监测及分析方法、常规监测技术对比分析、工程实践应用等研究,论证了分布式光纤测温技术应用于堤坝渗漏监测的可行性和适用性。布里渊测温系统受温度和应变影响,测值波噪明显,光纤埋设及保护要求较高,拉曼测温系统可测得绝对温度,其测温稳定性及精度均优于布里渊测温系统;加热法和梯度法监测渠道堤坝渗漏在技术上均可行;分布式光纤测温技术具有监测距离长、空间分辨率高、远程线性测量等特点,在渠道堤坝渗漏监测实践应用中具有显著的技术优势。

Experimental study of distributed optical fiber temperature measurement technology for measuring leakage in embankment dam

The technology of temperature measurement by distributed optic fiber is introduced in this paper. By laboratory tests and field tests, comparison and selection of distributed temperature measurement optic fiber, analysis of its accuracy and stability, monitoring and analyzing leakage in the embankment dam using distributed optic fiber, comparing with conventional monitoring technology, and it’s engineering applications are carried out. Based on these tests, the feasibility of and applicability to the monitor of the leakage in the embankment dam using distributed optic fiber are discussed. The technology of temperature measurement by distributed Raman optic fiber, whose sensitivity of temperature is ±0.5 ℃, is feasible in monitoring leakage in the embankment dam using temperature gradient analysis method and heating method. Comparing with the results measured by conventional monitoring technology, the accuracy of data measured by distributed Raman optic fiber and its reliability of monitoring leakage in the embankment dam have been verified. Monitoring leakage in the embankment dam using distributed optic fiber has obvious advantages, such as distributedness, long range and anti-interference.