Brief Introduction To Vacuum Preloading

Brief Introduction To Vacuum Preloading

Vacuum preloading

The vacuum preloading method is to set up prefabricated vertical drains or sand well in the soft clay, and lay a sand layer on the upper layer, and then cover the film to seal, and pump the gas to make the drainage band and the sand layer in the membrane partially under vacuum, and remove the moisture in the soil. A ground treatment method that pre-consolidates soil to reduce sedimentation in the later stages of the foundation.

The principle of vacuum preloading is mainly reflected in the following aspects:

1) The film is subjected to a load equal to the pressure difference between the inside and outside of the film.

2) The groundwater level is reduced and the additional stress is increased accordingly.

3) The closed bubble is discharged, and the permeability of the soil is increased.

The vacuum preloading is performed by vacuuming under a sealing film covering the ground, and a pressure difference is formed inside and outside the film to cause a consolidation pressure of the clay layer. That is, a method of increasing the effective stress by reducing the pore water pressure while the total stress is constant. Vacuum preloading and precipitation preloading are drainage consolidation under negative superhydrostatic pressure, known as negative pressure consolidation.