2. Casing pipe is driven into the ground using a vibro-hammer.
3. When it reaches the required depth, the casing pipe is charged with a specified volume of sand.
4. As the casing pipe is raised by a specified margin, the sand is discharged into the ground using compressed air.
5. The sand pile is compacted and enlarged by driving the pipe back down into the sand.
6. The pipe-raising, sand discharge and re-driving procedure is repeated numerous times as the pipe is gradually removed, forming a complete compacted sand pile.