| Author | Mampitiya, Arachchige Ajith Shanthadeva |
| Call Number | AIT Thesis no.GT-86-01 |
| Subject(s) | Peat--Sri Lanka--Colombo
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | A series of isotropic ally consolidated triaxial compression tests
along the conventional stress paths, namely, undrained, drained and
anisotropic compression paths were carried out on undisturbed peat samples consolidated at low stress levels . These samples were recovered from
the city of Colombo, Sri Lanka. The compressibility characteristics were
studied in the Casagrande oedometer and samples were observed for the
secondary compression response on a long term basis under different stress
increment ratios. All sampling was carried out with a thin-walled sampler
and a box sampler.
The undrained behaviour is characterized by very high effective
friction angles and were mobilized under large strains. No significant
strain softening was observed. The drained behaviour was similarly marked
by extremely large strains and high friction angles. However limiting
stress conditions were not attained in the drained tests. The incremental
stress strain theory of Roscoe & Poorooshasb was successful in predicting
the strains in the drained tests.
The compressibility characteristics of the samples as a equilibrium
void ratio - effective stress relationship showed marked linearity on the
double logarithmic representation of specific volume versus effective
stress as proposed by Butterfield. The time settlement curves showed the
S-shaped curves at low stress increment ratios. The ratio of secondary
settlement over primary settlement was greater than unity for low stress
increment ratios and decreased with increasing stress increment ratio.
Various linear and nonlinear rheological models were tested and the
best prediction was obtained by Garlanger's model . It was ammended in
this study incorporating the suggestion of Butterfield and this ammended
model gave the best prediction. Terzaghi's theory was in good agreement
with the observed primary consolidation settlement for higher pressure
increment ratios. |
| Year | 1987 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Geotechnical and Transportation Engineering (GT) |
| Chairperson(s) | Balasubramaniam, A.S.
|
| Examination Committee(s) | Towhata, I. ;Bergado, Dennes T.
|
| Scholarship Donor(s) | The Royal Netherlands Government |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1987 |