| Author | Ratnayake, A. M. P. |
| Call Number | AIT Thesis no.GT-90-06 |
| Subject(s) | Embankments
|
| 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 |
| Series Statement | Thesis ; no. GT-90-06 |
| Abstract | The work presented in this dissertation is a detailed study on the performance of two
embankments, one without vertical drains and the other with vertical drains at the Muar flats site
in Malaysia. The clays in the sub-soil were modelled according to the Critical State Theories
and in particular, the modified Cam-clay theory. Fully coupled Biot's consolidation analysis
was conducted with five different finite element models using CRISP program in which either
the linear strain triangles (LST) or the linear strain quadrilaterals (LSQ) can be incorporated as
appropriate elements. The embankment without vertical drains was analyzed using the stress
path dependent soil properties.
A proper selection of soil parameters based on the applied stress paths, which are different
from those obtained from conventional CK0U compression tests are incorporated in the finite
element analysis with coupled consolidation theory. From this analysis, the excessive lateral
displacements at greater depths and excessive heave close to the toe of the embankment without
drains which were evident from the previous predictions were reduced to match the field behavior.
The analysis on single drain including a simplified solution technique (Barron's theory of
consolidation) as well as the finite element analysis with axi-symmetric condition indicated that
the smear effect and well resistance as traditionally analyzed can be neglected in explaining the
lower efficiency of band type of drains. If the efficiency of the drains were assumed as 100%
then the computed consolidation settlements considering the influence zone of the whole
embankment agreed well with the values obtained from the single drain analysis whereas the
field values are smaller. A further analysis conducted with an assumed undissipated excess pore
water pressure at the drain boundaries revealed a measure of deficiency in the drain performance
in a quantitative manner. These undissipated pore pressures at the drain boundaries gradually
reduced with time from a full value of 100% just after loading to 16% after 105 days (at the end
of first stage of loading). For the second stage of loading these values again reduced from 100%
at the start and then to 18% after a period of 284 days. Thus there appears to be a sharp gradient
of pore pressure between the drains and the adjacent clay surfaces which obstructs the full
efficiency of the drains. |
| Year | 1991 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GT-90-06 |
| 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. ;Indraratna, B.
|
| Examination Committee(s) | Honjo, Yusuke ;Bergado, Dennes T.
|
| Scholarship Donor(s) | The Canadian International Development Agency,
A I T Partnership Program; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1991 |