| Summary: | 碩士 === 國立海洋大學 === 河海工程學系 === 90 === The object of this study is to simulate the properties of silty sand eroded due to acid rain. The test method is by soaking the compacted soils in different pH values of artificial acid rain for 1, 3 and 5 months long, respectively. The variation of ψ values was obtained via direct shear tests to evaluate the influence of acid rain on shear strength of the specimens. In addition, the changes of acid rain on components and framework of soils were conducted by proceeding X-ray diffraction test and using scanning electron microscope.
The results of experiment indicate that the ψ value of compacted silty sand decreases with decreasing of pH level of acid rain and of soaking period. The pH values of the specimens also should similar situations. The reason for the decreasing of pH values of the soils is the chemical reactions between the soils and the acid rain. Furthermore, it was found that the sulfur ions of acid rain tend to lubricate the particles in soils and hence reduce ψ values. Increasing soaking time, the content of acid rain also increases, hence, the specimens were softened and were easily to be sheared .
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