It has always been a difficult problem to determine the safety interval of vibration during the construction of dynamic compaction machine, which involves the determination of Safety specifications, the characteristics of foundation soil, the size of dynamic compaction function level, the size of rammer area and many other elements.
It is difficult to give proper data without on-site vibration inspection, but not every project has the conditions to do on-site vibration inspection, especially in the initial stage of foundation treatment plan.
The vibration produced by dynamic compaction machine has the following rules:
1) The main frequency of dynamic compaction machine vibration is generally below 50 Hz, and decreases with the increase of interval.
2) In a short interval, the vibration wave of dynamic compaction machine is mainly loose to the surrounding by surface wave. The vibration intensity decreases with the increase of the distance from the vibration source. The attenuation rate of vibration intensity is related to the characteristics of foundation soil. When the local foundation soil layer is fragile, lax, low density and thick, the vibration intensity is attenuated and active; When the local foundation soil layer is stable and dense, or the soil layer is fragile and thin, and the underlying soil layer is stable, the vibration intensity attenuation is slow.
3) When the vibration source point of dynamic compaction machine is located at the lower part of the relative elevation, the vibration effect at the higher part of the relative elevation is expanding; When the vibration source point of dynamic compaction machine is located at the higher relative elevation, the vibration effect at the lower relative elevation is attenuation.
4) The vibration intensity increases with the increase of energy level and decreases with the decrease of hammer area.
Dynamic compaction machine is mainly used in construction. Due to the need of soil compactor, dynamic compaction machine is often used in the construction of dynamic compaction machine. There are many types of compaction machine, such as frog, vibration type, step by step, tamping, hanging hammer type. According to the needs of the project, different types of dynamic compaction machine are used to fix the foundation.