Soil compaction assessment on unpaved road surfaces using ground penetrating radar and time domain reflectometry

초록

Soil compaction plays a crucial role in geotechnical engineering and influences stability and load-bearing capacity of unpaved roads. This study evaluates the applicability of ground penetrating radar (GPR) and time domain reflectometry (TDR) for assessing soil compaction on unpaved road surfaces. A field test was conducted using two distinct compaction methods: repeated dump truck passes (0, 100, 200, and 500 times) and water compaction (measured after 3 and 9 h). GPR images, direct wave signals, and TDR measurements were analyzed to examine the relationship between the travel time, amplitude, and relative permittivity. The results indicate a strong linear correlation between the direct wave travel time and the square root of the relative permittivity, demonstrating the potential of GPR as a noninvasive compaction assessment tool. Wavelet transform analysis effectively distinguished between direct-air and direct-ground waves, confirming that the direct wave is primarily composed of a direct-ground wave. However, attenuation effects, particularly in water-compacted soils, affect amplitude-based interpretations. The integration of GPR and TDR provides a comprehensive approach for evaluating soil compaction, with the direct wave travel time potentially serving as an indicator of relative permittivity variations.

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