Improvement of fine-grained and cohesive soils 115
submersible stone storage systems allowing the usage of moderate size
cranes for the construction of stone columns to great depths without compromising their quality and execution accuracy.
4.3 PRINCIPAL BEHAVIOR OF VIBRO STONE
COLUMNS UNDER LOAD AND THEIR DESIGN
4.3.1 Overview and definitions
Vibro stone columns are in general used to improve characteristics such
as the strength and compressibility of fine-grained cohesive soils that are
deemed insufficient for the geotechnical purpose. These soils are predominantly water-bearing silty and clayey sands, sandy silts, and silt and clay
mixtures. Their main characteristics, water content, consistency, and shear
strength, are shown in Figure 4.7. These soil properties, together with those
of the stone columns, influence the behavior of the composite soil–stone
column matrix.
Certain definitions and some of the terminology used in conjunction
with ground improvement by vibro replacement stone columns are further
Figure 4.5 Crane-hung dry bottom feed system for deep stone columns (S-Alpha system).
(Courtesy of Keller Group plc, London, UK.)