The pile mechanism of high-pressure jet grouting includes the following five functions:

(1) High-pressure jet stream cutting action on soil. The jet flow impacts the soil with pulsating pressure, creating cavities and expanding soil fissures.

(2) Mixing and Agitation Effect. During the rotation and lifting process of the drill rod, a cavity is formed at the rear of the jet stream. Under the pressure of the jet, the soil particles are forced to move in the opposite direction to the nozzle's movement (i.e., the direction of less resistance), changing their position and mixing with the slurry to form a new structure.

(3) Lift and Displacement Action (Triple Tube Method). While cutting soil with high-speed water jet, compressed gas is introduced to expel a portion of the cut soil particles to the ground. The resulting voids are then filled with cement slurry.

(4) Filling and consolidation through penetration. The high-pressure cement slurry quickly fills the gaps in the slots and between soil particles, solidifies upon water extraction, and can also penetrate into the sand layer to a certain thickness, forming a solidified mass.

(5) Compaction Effect. During the cutting and crushing process of the soil layer by the high-pressure jet stream, there is still residual pressure at the edge of the crushed area, which can exert a certain degree of compaction on the soil layer. This results in the edge section of the jet grout pile having a higher compressive strength than the central section.