1. Introduction

The deep vibratory compaction technology, invented by Johann Keller in the 1930s in Germany, is a ground improvement method using vibrational energy. Among its applications, deep vibro stone columns are widely used for reinforcing soft clay soils. This technique involves forming compacted columns of aggregate within the soil, which serve to: (1) reduce settlement; (2) improve load-bearing capacity; (3) mitigate liquefaction potential; and (4) expedite drainage and consolidation of the soil foundation.

During construction, a deep vibrator is used to create stone columns of specified diameter and depth, densifying the surrounding soil layers to increase foundation stability. Typical stone column diameters range from 0.7 to 1.2 m, with spacing between columns set at 1.5 to 3.0 m, depending on design requirements. Stone columns can reach depths up to 20 m, making this technique highly effective for strengthening foundations in soft soils.

2. Scope of application

Due to its adaptability, deep vibro stone column technology is widely applied to reinforce various soil types, including loose sandy silt, soft clay, very soft silty soil, clayey silt, and peat. Specifically, deep vibro stone columns are suitable for large-scale projects such as transportation infrastructure, port facilities, industrial buildings, plants, and storage tanks.

3. Construction sequence

There are 02 common methods for installing deep vibro stone columns: (1) bottom-feed (dry process) and (2) top-feed (wet process). The process of stone column construction using the bottom-feed method is illustrated in Fig. 1.

Figure 1. Construction sequence of stone column construction using the bottom-feed method

4. Technology video