Geoscience Reference
In-Depth Information
Figure 6.15
Systems in jet grouting (
after
Keller Holding, 2005; Kazemian and Huat, 2009b).
Table 6.2
Methods used in DMM (
after
Kenneth and Andromalos, 2003; Kazemian and Huat, 2009b)
Jet grouting systems
Shallow
Deep soil
soil mixing
mixing
Single
Dual
Triple
Super jet
(SSM)
(DSM)
phase
phase
phase
grouting
Ras-columns Cement
I. Maxperm grouting system
Dry jet
Jumbo
Ras-jet system
Deep Mixing
II. Navigational drilling system mixing
eco pile
System (CDM)
III. Vacuum grouting injection
system system
(DJM)
(JEP)
III.
Triple phase (water
+
air injection and followed by grout injection).
IV.
Super Jet Grouting (air injection
+
drilling fluid by grout injection).
Figure 6.15 shows the procedure adopted in the jet grouting systems.
It is important to note that DMM are divided into three types, namely SSM (Shal-
low Soil Mixing), DSM (Deep Soil Mixing) and JGS (Jet Grouting Systems); Table 6.2
clearly names the methods which are utilized in each type (Kenneth and Andromalos,
2003).
6.4.1 Ras-columns
Ras-columns is one of the most common soil mixing methods in DDM, based on
mechanical soil mixing technology. This method has been used for improving shallow
soils and seldom in deep mixing (Kazemian and Huat, 2009b).
Columns of stabilized material are formed by mixing the soil in place with a
'binder'. The interaction of the binder with the soft soil leads to a material which has
better engineering properties than the original soil (Hebib and Farrell, 2003).
The mixing head is combined with blades which can rotate inversely. In other
words, in the bottom auger the mixing blades rotate clockwise and in the upper auger
they rotate anticlockwise (Raito Kogyo, 2006).
This technique causes the cement to mix with soil homogeneously and thus pro-
duces higher quality soil-cement columns. The first step in this method is rig positioning
