Research on the Vibration Attenuation Rules and Wave Propagation Law under Impacting Drill on the Deep Soil Layer

A field test is carried out to study the effect of vibration while treating foundation using vibroflotation method in the deep soil layer in Zhengzhou, China. The vibration attenuation rules and wave propagation rules in different formations caused by different numbers of drills are analyzed. Evaluate the influence on the adjacent buildings. The result shows that the vibration will be generated in foundation obviously in the process of construction using the method. Vibration force, impact frequency and site soil are important influence factors on ground vibration attenuation. The analysis reveals that the maximum vertical acceleration attenuation velocity was much greater in near area than that in the relative far area. The waves caused by vibration propagate in two ways: (1) surface wave is generated on the wall of drill hole and propagated to the ground surface, and attenuated in a certain distance (<8m); (2) shear wave was generated and propagated in the impacting formation and attenuated from the deep formation to the ground surface. Vibration amplitude is mainly distributed in the low frequency range in the areas which far away from vibration source and in the silt layer near the ground surface.