The vibro compaction of sandy soil is the technology of using the vibration load to rearrange the particles and reduce the volume and become dense sand.the
For saturated soil, under the repeated horizontal vibration stress ,soil water pressure increases quickly, the connect force between soil particles decrease, and the soil particles are transferred to the lower potential energy, forming a tight stable structure to adapt to the new stress condition.
1) Vibration and extrusion: The horizontal vibration force of the vibroflot is transmitted through the soil skeleton to compact the surrounding soil.
2) Vibration float: Vibration cause the increase of water pressure in the surrounding soil, which leads to the destruction of the structure of the soil particles and formation of a new stable structure.
3) Consolidation: When the water pressure dissipates under the effect of stress on the sand soil, the consolidation is generated.
It is often used to improve the foundation of cohesive soil. It is to use the vibration and high pressure water shocking, forming the gravel pile in the foundation, so as to form a composite foundation bearing system with the foundation soil, to achieve the purpose of improvement.
1) Pile effect:The pile with higher strength can reduce the additional stress of the foundation soil through the stress concentration.
2) Cushion effect: The stress exerted by the foundation is not only passed down from top of the pile, but also through the lateral deformation of the pile body to the surrounding soil. The composite foundation is equivalent to a stiffened artificial cushion with better diffusion properties.
3) Drainage: The good drainage performance of the pile helps to consolidation the viscous soil with high moisture content, thus improving the strength of cohesive soil. At the same time, when the building load applied, the super-void water pressure generated in the foundation soil can dissipate rapidly, so that the consolidation settlement can be completed quickly.