土石坝渗流监测的光纤光栅-水暖循环集成系统及其关键技术

Based on heating method in the temperature tracer method, a new monitoring system that can be applied on the seepage monitoring of rock-fill dam is presented by embedding the fiber Bragg grating (FBG) in the pipes of the water cycling heating system. This new system can be expected to solve the defects of e.g. spatial discontinuity and inefficiency in the current traditional mode. The main substructures of this integrated system are composed by electric boiler, sub-water catcher, heating pipeline, and FBG temperature sensors which will play the function of heating, allocation, transporting and monitoring, respectively. The temperature distribution of heated water along the pipeline can be measured by embedded FBG, and then the seepage field will be derived from the relevance of temperature field and seepage field. Based on seepage mechanics and heat transfer theory, a synthetically method is presented for the quantification calculation of the seepage velocity by combining with experiment calibration, numerical simulation, monitoring data and neural network inversion analysis. To verify the capacity of monitoring system and the validity of the quantitative identification method for the seepage velocity, a series of experiments that take the influence factor of leakage passage and leakage intensity into account are designed for simulating the concentrated leakage of rock-fill dam. This project, with novel academic thought and advanced research techniques, will have broad engineering application prospect and promote the development of monitoring science and technology in civil engineering and hydraulic engineering.

以土石坝渗流监测为研究对象，基于温度示踪法中的加热法，提出将光纤光栅温度传感系统与水暖循环供热系统相结合的新型监测体系，解决目前常规监测手段空间不连续、效率低等缺陷。该集成系统采用电热锅炉作为加热设备，热水通过分集水器分配到各条供暖管路进行循环加热，光纤光栅温度传感器预埋在供暖管内测量管道内热水的沿程温度分布，根据温度场与渗流场的相关性间接获得渗流场。基于渗流力学与传热学理论，提出将试验标定、数值仿真、监测资料和神经网络反演分析相结合的渗流速度综合分析方法。构建土石坝集中渗漏的试验模型，考虑渗漏通道的数量、位置及渗漏强度等影响因素进行多工况试验，验证监测系统及渗流速度量化识别方法的有效性。该项目学术思路新颖，研究手段先进，工程应用前景广阔，有利于促进土木水利工程监测科技的发展。

以土石坝渗流监测为研究对象，基于温度示踪法中的加热法，提出了将光纤光栅温度传感系统与水暖循环供热系统相结合的新型监测体系，解决目前常规监测手段空间不连续、效率低等缺陷。该集成系统采用锅炉作为加热设备，热水通过分集水器分配到各条供暖管路进行循环加热，光纤光栅温度传感器预埋在供暖管内测量管道内热水的温度，根据温度场与渗流场的相关性间接获得渗流状态。为了解决光纤光栅传感系统的空间分辨率问题，在光纤光栅-水循环加热渗流监测系统的基础上，提出将聚四氟乙烯管（内管）与PE-RT供热管（外管）组成双管结构，光纤光栅传感串在内管中通过自由拖动改变测点位置以提高空间分辨率的移动分布式渗流监测方法。基于牛顿冷却定律，提出了根据管路降温曲线拟合出系数ζv并将其作为判别指标识别渗漏状态的新方法。建立了线热源在多孔介质中传热的数值模型，并进行了多工况数值仿真；开展了渗流速度的标定试验、集中渗漏监测的模型试验。结果表明：该监测系统灵敏度高，可在测点有限的情况下提高空间分辨率，从而较好地进行渗漏区域的定位；通过渗流标定试验可预先建立ζv与渗流速度的量化关系，从而实现渗流速度的量化。