Geoscience Reference
In-Depth Information
dry form. The moisture in the soil is utilized for the binding process, resulting in an
improved soil with higher shear strength and lower compressibility. The removal of the
moisture from the soil also results in an improvement in the soft soil surrounding the
mixed soil. Dry DSM methods have been used in Sweden and Finland since 1967 for
soil improvement in soft clays and organic soils, and are mainly used to increase sta-
bility and reduce the settlements of embankments. A typical dry DSM unit consists of
a track-mounted installation rig fitted with a leader and a drill motor, as shown in Fig-
ure 6.13. The binder is carried in pressurized tanks, which are mounted on the rig itself
or on a separate shuttle, as shown in Figure 6.13. Soil columns up to 14m long have
been constructed using this method. Figure 6.14 shows a typical embankment section.
The Deep Mixing Method (DMM) is today accepted worldwide as a soil improve-
ment method which is performed to improve the strength, deformation properties and
permeability of the soil. It is based on mixing binders, such as cement, lime, fly ash
Principle of LC-Column production
(a)
(b)
Tank
BINDER
KELLY
Cell feeder
GROUND LEVEL
MIDONG TOOL
LC-COLUMN
(c)
Figure 6.13
(a) Schematic showing a dry DSM machine installing columns; (b) photo showing the
ejection of the binder from the mixing tool in a dry form; (c) schematic showing mixing
operation in dry DSM process (
Source
: LCM Marktechnik).
