GROUND VIBRATION INDUCED BY MAN-MADE ACTIVITIES IN THAILAND

Abstract

The sources of ground vibration frequently seen in Thailand are pile driving, road construction and blasting. The magnitude of such vibrations from these activities can be estimated by empirical formulas which were reported in literatures. However, few of them were based on studies in Thailand. This study is an attempt to validate and propose equations for estimating vibrations due to man-made activities based on field measurements. The result from this study should reflect domestic ground conditions and work practices and should be useful for preparing vibration mitigation and monitoring plans in Thailand. It was found that vibrations due to pile driving and blasting can be divided into two zones. The vibrations in the near field were dominated by body waves while the ones in the far field were dominated by surface waves. The near field for pile driving ranges between 0.6-1.9 times of pile penetration depth. For blasting, the near field condition occurred when the distance was less than 70 ~ 150 m. The geometric damping parameters for the near and far fields were found to be 1.5 and 0.5, respectively. For vibratory compaction, it was found that surface waves were the most influential wave type. The geometric damping parameter for this case was found to be 0.5. Using the prediction models proposed in this study and guidelines in DIN 4150, the recommended setback distances for residential buildings are as follows; 1) 1.6 times of pile length when driving a pile in dense sand 2) 1.1 times of pile length when driving a pile in stiff clay 3) 53, 149 and 221 m for rocky, sandy and clayey ground when blasting by 2kg explosive 4) 5.5 m for a vibratory roller with weight less than 20 tons.