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Distributed optical fiber sensing technology, with its huge advantage began to be applied by the researchers in monitoring the leakage, but how to use what kind of distributed optical fiber technology, laying optical fiber and what is the scope of application and many issues, has not solved. This paper conducted the following research:1, This paper compares the advantages and disadvantages of six kinds of leakage monitoring method, analyzed the distributed optical fiber temperature sensing technology used in the theoretical feasibility of seepage monitoring, also Analyzes the characteristics of the distributed temperature sensing technology based on the Rayleigh, brillouin and Raman scattering principle, and build a set of distributed optical fiber sensing monitoring system of leakage.2, The calculation method of the two-dimensional steady anisotropic seepage and the calculation equations of temperature field under the action of seepage field is proved theoretically to provide theoretical support for the analysis of temperature field.3, According to the result of laboratory test and field test, this paper analyzes the brillouin and Raman method on the seepage monitoring of stability and precision, and evaluate the feasibility, applicability of the two methods and applicable conditions. And also analyzes the advantages and disadvantages and applicable conditions of gradient method and heating method of the Raman method monitoring seepage. Combining with the experience of fiber laying, provides some suggestion about optical fiber laying position, method and attention points.4, The finite element model of dam seepage flow field and temperature field is presented and seepage and the temperature field contours is obtained. This paper analyzes the dam body and foundation seepage about water head, cross section flow, the seepage line, seepage path and velocity vector distribution and the distribution of the temperature, focuses on the maximum velocity and maximum temperature gradient in the dam foundation of two-dimensional distribution, according to the calculation results to determine the optical fiber laying the best place.Through the results of field test and finite element model analysis, can get the following important conclusions:1, Brillouin and Raman method has the feasibility on the seepage monitoring, the former is more need to pay attention to protection work, the latter has more advantages on the stability, accuracy, and environmental impact resistant ability.2, Heating method can improve the seepage monitoring sensitivity but not more practical than gradient method, must be cautious to use in practical engineering with a lot of hidden trouble.2, The best laying position of distributed optical fiber is the bottom of the dam body and outside near the slope toe, and the farther from the slope toe, the deeper optical fiber must be buried.
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