Load-settlement analysis of bored piles in Bangkok sub-soils using the finite element method | |
| Author | Fernando, Geekiyanage Sarath Kumara |
| Call Number | AIT Thesis no. GT-91-02 |
| Subject(s) | Soil mechanics--Thailand--Bangkok Finite element method Borings--Thailand--Bangkok |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineeiing. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GT-91-02 |
| Abstract | CRISP Finite Element Program has been used to analyze the behavior of two bored piles namely BPl and BP2, with pile tips in the stiff clay layer and in the first sand layer respectively. The clay layers are assumed to behave according to Modified Cam Clay model. The sand is assumed to follow elastic-perfectly plastic model. A special interface element with finite thickness obeying the elastic-perfectly plastic law has been used to model the interface defotmation modes. For the both piles the analysis has been carried out under undrained conditions. The consolidation analysis has been done for the pile BPl ending in stiffclay layer. The finite element results are then discussed with respect to load-settlement characteristics, load transfer characteristics, intetface slippage, consolidation settlements and pore water pressure development during the pile loading. A parametric study has also been carried out to examine the sensitivity on pile settlement. The finite element results have clearly shown the applicability of Modified Cam Clay model for clays and elastic-perfectly plastic model for sands for load settlement predictions of bored piles in Bangkok soils. For the pile BPl, load-settlement prediction by Modified Cam Clay model agree reasonably well with actual measurements.Forpile BP2, theprediction shows clear deviation from actuality at a load of 330t. The predicted load transfer curves confirm the high skin capacity of stiffclays and sands making the pile floating type depending on the depth of embedment. The measured load transfer of pile BP2 agreed reasonably well with the predictions up to a load of 330t, at which the predicted load-settlement curve deviates from actual. The relative slippage between pile and soil initially starts at top and propagates downward for both cases. Slippage can also start close to pile tip, moving up with increasing tip load. The pile head displacements for full mobilization of skin friction for soft clay, medium clay and stiffclay are found to be very small. The displacementfor full mobilization ofgross skin friction for pile BPl is approximately 0.35% of the pile diameter. The pore water pressure increase around the shaft is negligible for both piles but directly below the pile tip it is significant. Consolidation settlements are negligible when compared with immediate settlements. For the piles in sands, the influenced zone by shear close to pile tip is considerably higher than that of pile in stiff clays at the same load. The influenced zone around the shaft by pile settlement is proven to be approximately 10 times the pile diameter. |
| Year | 1992 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GT-91-2 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical and Transportation Engineering (GT) |
| Chairperson(s) | Balasubramaniam, A. S.; |
| Examination Committee(s) | Honjo, Y.;Noppadol Phien-wej; |
| Scholarship Donor(s) | Asian Development Bank.; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology |