ABSTRACT
This chapter discusses aims to strengthen the existing soil by rearranging and compacting coarse granular particles to form stone columns with the ground. Applied to non-cohesive subsoils where the granular particles are rearranged into a denser condition by poker vibration. The crane-suspended vibrating poker is water-jetted into the ground using a combination of self-weight and water displacement of the finer soil particles to penetrate the ground. Vibration through the subsoil can be a problem with dynamic compaction operations; therefore the proximity and condition of nearby buildings must be considered, together with the depth position and condition of existing services on site. The probe is rotated and the sides of the borehole are subjected to a jet of pressurised water and air from a single outlet which enlarges and compacts the borehole sides. All subsoils have different abilities to remain stable during excavation works. Steel sheet piles can be used in excavations and to form permanent retaining walls.
