PVD improvement of soft Bangkok clay with vacuum and heat preloading | |
| Author | Suthasinee Artidteang |
| Call Number | AIT Thesis no.GE-08-06 |
| Subject(s) | Vertical drains--Thailand--Bangkok Clay--Thailand--Bangkok--Analysis |
| Note | A thesis proposal submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Geotechnical and Geoenv ironmental Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-08-06 |
| Abstract | This study was performed on a new large scale consolidometer in the laboratory by using reconstituted clay specimen from Suvamabhumi Airport site for enhanced PVD improvements of the soft Bangkok clay. A series of laboratory tests were conducted to investigate the behavior and compressibility characteristics of normal PVD, surcharge and vacuum pressure combined with PVD (Vacuum-PVD), heat combined with PVD (Thermo-PVD) and heat combined with Vacuum-PVD (Thermo-Vacuum-PVD) and improve the efficiency of PVD with the reduction of smear effect around the PVD. Vacuum pressures of -50 kPa was applied to the sample and heat applied up to 90°C. Water contents, shear strengths and heat transfers were observed at radial distances of 25, 50,100 and 200 mm from PVD. When the specimen was heated, the magnitude of settlements was higher and rate of consolidation was faster. The shear strength increased with increasing temperatures and decreasing of water contents. The specimens demonstrated volume contraction upon application of heat and vacuum pressure. The Ch and kh/ks values for normal PVD were 1.93 m²/yr and 3.0. Upon application of the vacuum preloading with PVD, the corresponding values were 2.23 m²/yr and 2.7. For the PVD with heat, the corresponding values were 4.17 m²/yr and 1.4. And fmally, for Vacuum-PVD combined with heat the values were 4.38 m²/yr and 1.1, respectively. Scanning Electron Microscope images at 15,000 magnifications showed that undisturbed and reconstituted clay have dispersed microstructure arrangement. For the samples treated with normal PVD has less preferred orientation but for Vacuum-PVD sample has mixed with dispersed microstructure. The microstructure became flocculated after treatment with heat. For combined Vacuum-PVD with heat, the microstructure became more flocculated. In addition, Image Pro Plus 6 software was used to analyze images at 3,000 magnifications of SEM. The results show percent of porosity, contact zone and particle images. Vacuum-PVD images near and far from PVD have not much difference from normal PVD but have lower orientations of particles and higher percent 0 f porosi ty than Thermo- PVD. Whil e the combined Vacuum - PVD with heat images yielded with less porosity and higher orientations of particles. The better orientation was found at near PVD at the smear zone than far from the PVD at undisturbed zone. The Electric Imaging survey was measured on specimens and it had shown that the specimens became drier after consolidation in the middle and below the surface due to the effects of PVD with different enhanced treatments |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-08-06 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Bergado, Dennes T.; |
| Examination Committee(s) | Park, Kyung Ho;Pham Huy Giao; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2009 |