| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 98 === Many roadwork related issues, such as the thickness of pavement layer, poor grading of backfill material, or poor compaction of backfills may cause extensive road damage. The Ground Penetration Radar can be used to detect the defects mentioned above rapidly.
By using 250 MHz, 500 MHz and 1000 MHz antenna with RAMAC Ground Vision software, the effects of antenna frequency and filtering techniques on the GPR images were studied.
Results of this study show that：(1) The GPR images are affected by the grain size of the subgrade due to the diffraction phenomenon. (2)With suitable frequency of antenna, the boundaries between pavement, subgrade and base material can be identified. (3)A 1000MHz antenna is more suitable to detect the thickness of pavement. The depth of subgrade, or base material can be detected using antenna frequencies of 500MHz and 250MHz. (4)With Band Pass filter and Automatic gain control, the boundaries between pavement, subgrade and base material is more easy to interpret in the GPR images.
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