| In the word ,more than 40% of dam failures has are caused by seepage. It is generally recognized that the seepage monitoring is one of key items of dam safety monitoring.Engineering experience have shown that traditional electrical seepage meters posses considerable limitation It is necessary and urgent to develop a kind of high-tech seepage sensors in order that the internal seepage conditions of these projects could be monitored continuously, spatially, sensitively, and more reliably. Using Fiber Bragg Grating (FBG) sensing technology that has come into being recently, this paper has strived to develop FBG hydraulic seepage sensors.Fiber optic sensors are typical of hi-tech applied technology of marginality, involving much special knowledge of manifold subjects such as photo-electronics, fiber optic technology , material science, mechanics, engineering science and so onA series of structural analysis and tests of sensing probe encapsulation shell has been performed; Adopting nonlinear finite element numerical modeling, the micro-interface mechanics problem of optical fiber /base material complexes has been analyzed profoundly. This problem determines whether optical fiber sensors could be put into practical use. Moreover, the research into and tests of reflective fiber optical hydraulic seepage has been done in this treatise.The three dimensional nonlinear finite element analysis of interfaces mechanics have been performed for these two complexes and the tangent stiffness tests for fiber optic /concrete complex and fiber optical /glue complex have been performed for the first time. Parameters of nonlinear analysis are obtained, and the stress distribution in fiber-optic- concrete complex is presented. The problem of load transferring between elements of different freedoms has been lubricated. The finite element analyses of the encapsulation shells according to two kinds of glues have been performed. The adhesive material of high elastic module has been determined selectively. Its mechanics constants have been measured.Using finite element software ANSYS6.1, the mechanics analysis of sensing probe integral structures are performed. The surface shape and geometric specifications have been determined comparatively. The optics and mechanics transferring formula between FBG center reflective wavelength shift and seepage is given, and the possible measurement resolution of seepage is analyzed simply. Meanwhile, various experiments with fiber optic embedment into encapsulation, high pressure strength experiment of encapsulation shell, and manufacturing experiments of encapsulation shell integral structure have been conducted.Through the improvements of fabrication craft of many times, the Toroidal shape encapsulation shell has been made.In addition, The FBG sensing model under axial even shear has been analyzed; The relations between FBG reflective spectrum response function and shear under this mechanics has been inferred; More systematic FBG sensing modes under random stress and whole BGF sensing models considering temperature effects have been established.Serving as more simple fiber optic seepage sensing scheme without demultiplexing capacity, Moreover, the research of reflective fiberoptical hydraulic seepage has been done in this treatise. Its encapsulation shell is ellipsoid. Based theoretical model of FBG and Euler Equations, FBG Equation is inferred and dealt with systematically and rigorously. The FBG sensing model under axial even shear has been analyzed; The relations between FBG reflective spectrum response function and shear under this mechanics has been inferred; More systematic FBG sensing modes under random stress and whole BGF sensing models considering temperature effects have been establishedThrough the work done above, major conclusions are drawn as follows:1. Compared with traditional electrical seepage sensors ,the FBG seepage sensor owns several advantages, lying as: simple sensing mechanism, high discernibility, anti electromagnet interferenc...
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