| Author | Somasundaram, Sujithan |
| Call Number | AIT Thesis no.GT- 80-10 |
| Subject(s) | Subsidences (Earth movements)--Thailand--Bangkok--Statistical methods
|
| Note | A thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | This study is concerned with the application of probabilistic techniques in the prediction of compression of clay layers, due to the withdrawal of groundwater in Bangkok. The inherent uncertainty associated with compressibility characteristics of clays, are introduced into the analysis in order to obtain a probabilistic estimate of compression.
First the probabilistic description of the relevant soil properties were determined, based on the results of 588 consolidation tests carried out in the study area. A modified compression index was defined over the stress range of interest to this study. Using standard model verification tests it was established that model compression index is best represented by a two-parameter beta distribution, while void ratio, compression ratio and effective overburden pressure are normally distributed.
Based on the available records of piezometric pressure variation with depth, three typical areas with different drawdown patterns were identified in the study area. The typical piezometric pressure profiles in each of the three zones were determined.
A probabilistic model was developed for the prediction of compression, using the linear e-log P relationship and the determined distributions of the relevant soil properties. Using simulation techniques and treating drawdown as a determined input to the probabilistic model, probability distributions of compression in the first clay layer were estimated. The model was extended for simulation of compression in deep zones up to a depth of 100m, on the basis of sparse data available for the zone.
The model results for compression were found to follow a normal distribution with a coefficient of variation around 0.27. The Model was found to be satisfactory since the results agree quite well with field measurements even though the model results tend to be on the higher side of the observed values. The model was then employed to make probabilistic predictions of ultimate compression in the first clay stratum which was found to be 80.7 cm with a coefficient of variation of 0.25, in the severe case. |
| Year | 1981 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical and Transportation Engineering (GT) |
| Chairperson(s) | Jersasak Premchitt
|
| Examination Committee(s) | Balasubramaniam, A.S. ; Tomiolo, Andrea |
| Scholarship Donor(s) | Government of Norway |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1981 |