| Summary: | 博士 === 逢甲大學 === 土木及水利工程博士學位學程 === 105 === At present, there are water leakages in some domestic dams. The reservoir water flows along the pipe-shaped discharge tunnel in the dam body, and then flows out from the downstream slope of the dam along with soil particles. When there are local water leakages, the cross-section of the pipe-shaped discharge tunnel expands rapidly, and can cause piping failure.
Piping failure is unstable behavior for a dam structure. This unstable behavior is caused by the continuous flow of water containing soil particles; hence, the ellipticity of the dam structure continues to be lost. Therefore, when carrying out reservoir safety assessment related to water leakages, once the seepage formula is used, it is impossible to obtain the assessment results related to water leakages due to the ellipticity of the seepage formula.
Since the analysis of an unstable structure related to water leakages is very complex, for the sake of simplicity, this dissertation takes the piping failure of Renyitan Reservoir spillway as an example. Firstly, the shear zone pattern around the spillway is proposed to evaluate the location of the pipe-shaped discharge tunnel. Then, a theoretical formula is used to calculate the critical bottom velocity of the particles needed to cause a piping failure in the pipe-shaped discharge tunnel. Through the above method, we can effectively obtain the dam piping failure path and cause.
Since the pipe-shaped discharge tunnel in the dam only exists in the shear bandings of a tectonic plate, it is suggested to amend the "Water Conservancy Construction Inspection and Safety Assessment Method" and "Water Conservancy Construction Inspection and Safety Assessment Technical Specification" to include both the vibration effect of a tectonic plate and the shear banding effect of a tectonic plate, so as to correctly guide the pipeline analysis and piping monitoring methods.
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