| Author | Santi Sangmala |
| Call Number | AIT Thesis no.GE-96-11 |
| Subject(s) | Soil consolidation test--Thailand--Bangkok
|
| Note | A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-96-11 |
| Abstract | This study presents the efficiency of two drainage systems of vacuum preloading with surcharge on Prefabricated Vertical Drain (PVD) improved soft Bangkok clay at Second Bangkok International Airport (SBIA) site. The study also assessed the feasibility of this technology as alternative or supplement to conventional surcharge techniques for ground improvement at the SBIA site. To measure the field soil parameters before/after vacuum preloading with different drainage systems with PVD and to compare the efficiency of two drainage systems were studied. The settlements were predicted by using the one-dimensional consolidation (Terzaghi, 1923) method, Skempton-Bjerrum(l 957) method, Asaoka (1978) method and the results were compared with the field observations. The two full scale test embankments have been constructed with two drainage systems, namely: by using geonet with PVD length of 15 m. and by using perforated pipe with PVD length of 12 m. Instrumentations included high air-entrainment piezometers to measure negative pore pressures, electrical piezometers to measure excess pore pressures, standpipe piezometer for pore pressure measurements, observation well to observe ground water level, inclinometer for lateral ground movement measurements, monitoring of the ground surface settlement and muti-point extensometers for deep settlement measurements. The soil properties before/after improvement were obtained from the results of laboratory and filed tests which included Atterberg limits, unconfined compression tests, unconsolidated undrained triaxial tests, oedometer consolidation tests,and field vane shear tests. Results indicate that the efficiency of vacuum consolidation of TV2 (with perforated pipe with PVD length of 12 m.) was about 50 percent. The efficiency of vacuum consolidation of TVl (with geonet with PVD length of 15 m.) was about 40 percent. The observed settlement, the lateral deformation behaviour and the shear strengths were normalised with the depth irrespective of the type of drainage system and length of PVD in two embankments. The final settlement of TV2 about 0.96 m was higher than TVl which has the final settlement about 0.75 m. The lateral movement which occur at 0 to 2 m depth of TVl was higher than TV2 about O.lOm. The lateral movement at very soft clay 2 to 8 m depth of TV2 was higher than TVl . The shear strength after improvement of TV2 was about 30 percent higher than TVl. When compared the efficiency of both embankments together, we found that the efficiency of vacuum consolidation ofTV2 was higher than TVl. Under better conditions with a more effective membrane seal, higher efficiency and greater equivalent surcharge heights can be achieved, making vacuum-assisted consolidation an economically viable alternative or supplement to mechanical surcharges. |
| Year | 1997 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-96-11 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Geotechnical Engineering (GE) |
| Chairperson(s) | Bergado, Dennes T.; |
| Examination Committee(s) | Balasubramaniam, A. S. ;Shibuya, Satoru; |
| Scholarship Donor(s) | Partial; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology |