Comparison of thermal and vacuum PVD soft clay improvement including SEM investigation | |
| Author | Yin Min Thann |
| Call Number | AIT Thesis no.GE-07-02 |
| Subject(s) | Vertical drains--Thailand--Bangkok Soil consolidation |
| Note | A thesis proposal submitted in partial fulfillment of the requirements for the degree of Master of Science in Geotechnical and Geoenvironmental Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-07-02 |
| Abstract | Undisturbed and reconstituted soft clay samples from Suvarnabhumi were consolidated in large and small consolidometer using vacuum PVD and thermo PVD. The values of ultimate settlement, coefficient of horizontal consolidation, Ch, and kh/ks were compared with those values obtained from samples consolidated without the use of vacuum and PVD. Vacuum pressure of 10 kPa and 15 kPa were used for both the undisturbed and reconstituted samples and the heated samples were subjected to temperatures less than the boiling point of water. All the specimens showed volume contraction due to heat and vacuum pressure. This contraction depended upon the heat and vacuum preloading. Higher temperatures resulted in faster rates and magnitudes of settlement. Higher shear strengths were achieved within a limited zone around the heat source; within a distance of 2 times the radius of the heat source. The Ch and kh/ks values for undisturbed samples without heat were 2.34 m²/yr and 5.1, Upon application of the vacuum pressure the values were 2.42 m²/yr and 4.7. For the heated samples, the corresponding values were 2.63 m²/yr and 4.5. The Ch and kh/ks values for reconstituted samples without heat were 1.35 m²/yr and 1.65, respectively. Upon subjection to vacuum pressure the values were 1.8 m²/ and 1.4. For the heated samples the corresponding values were 1.89 m²/yr and 1.2. For the large consolidometer with heat the Ch and kh/ks values were 2.55 and 1.2. Scanning Electron Microscope images and analyses of the images by intensity gradient method showed that natural and reconstituted clay have preferred (dispersed) structure. After treatment with heat, the microstructures of undisturbed and reconstituted clay samples become more random in arrangement than the non treated ones. The same microfabric change can also be noticed in the vacuum preloaded samples, but mixed with disperse microstructure arrangement. For the samples treated with PVD only, more or less preferred orientation can be seen |
| Year | 2008 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-07-02 |
| 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) | Noppadol Phien-wej;Pham Huy Giao; |
| Scholarship Donor(s) | ADB; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2007 |