Compressibility Characteristics of Fibrous Tropical Peat ... - Ejge.com

Vol. 14, Bund. C 8
Coefficient of consolidation, Cv
(m²/year)
5.4
4.9
4.4
3.9
3.4
2.9
2.4
1.9
0 100 200 300 400
Consolidation Pressure (kPa)
Untreated Peat
Sample A
Sample B
Sample C
Sample D
Figure 6: Coefficient of consolidation versus consolidation pressure.
Compression index (C c )
The rate of compression index in the standard consolidation test can be defined by the slope (C c )
of the final part of the void ratio versus logarithmic of load (log p) curve. Based on Figure 7, the
compression index (C c ) values from Rowe Cell consolidation test for the natural fibric peat,
sample A, B, C, and D; were 1.809, 1.723, 1.467, 1.343, and 1.098 respectively, for consolidation
pressure of 50 kPa. It means by increasing the cement ratio the compression index (C c ) is
decreased gradually. The fibrous reinforced peat is cured in water peat that’s why; it obtained a
little different of values with such other researchers.
2.1
Compresion Index, Cc
1.8
1.5
1.2
0.9
0.6
0 10 20 30 40 50 60
Cement Ratio (%)
Figure 7: Compression index versus cement ratio in peat soil.
Coefficient of secondary compression, Cα
For the following three reasons, secondary compression and associated settlement are often more
significant for peat deposits than other geotechnical materials: (1) fibrous peat deposits display
the highest values of Cc; (2) fibrous peat deposits have the highest values of C α /C c ; and (3)
primary consolidation of fibrous peat layers in the field is completed commonly within a few
weeks or months (Mesri and Ajlouni, 2007). Primary consolidation and secondary compressions
can take place simultaneously. However, it is assumed that the secondary compression is
negligible during primary consolidation, and is identified after primary consolidation is
completed (Lefebvre et al., 1984; Hobbs, 1986; Kogure et al., 1986).