Effect of Vacuum-PVD improvement on areas with and without filled-up canal at the Suvarnabhumi airport’s third runway project | |
| Author | Sapkota, Brabin |
| Call Number | AIT Thesis no.GE-22-12 |
| Subject(s) | Vertical drains--Thailand Geology--Thailand Clay--Thailand |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Geotechnical and Earth Resources Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | There has been a significant increase in the number of travelers using Suvarnabhumi International Airport, leading to an expansion project known as the 3rd Runway extension. The extension area was previously used for agriculture and swamp farming, with ponds and artificial canals nearby. However, due to the weak soil and high compressibility in the area, ground improvement was necessary. Vacuum PVD preloading was used to address these ground problems. The ground improvement project along the taxiway area involved backfilling in an existing canal in zone 29 and regular vacuum improvement in zone 27. The study aimed to compare the effects of improvement in with and without canal. It was divided into three main parts: field investigation, laboratory testing, and geotechnical analysis. In the field investigation, total five boreholes and three vane shear tests were conducted in both zones. The laboratory testing included water content, atterberg limit, and 1D consolidation tests on retrieved samples. In Geotechnical analysis, compared the pre- and post-improvement in both zones, and it was found that there was a significant change in soil properties from soft-medium stiff clay to medium stiff clay. Further comparison between the post-improvement within and without the canal area showed that the soil properties were different, with higher compressibility parameter and lower shear strength within the canal area compared to those without. A correlation analysis was conducted between undrained shear strength from a vane shear test and liquidity index, but the correlation was found to be very weak (r2=0.0296). The degree of consolidation was estimated using Asaoka’s, Hyperbolic and Hansbo's methods. Additionally, the Ch value was back-calculated using kh/ks=4 and ds/dm=2 from both zones, resulting in a range of 3.49 to 3.87 m2/year. Numerical analysis was performed for both zones and calibrated with field data. The calibrated model for zone 27 was used to investigate the effect of changing PVD design on improvement time and settlement rate. Results showed that PVD spacing had a significant impact on settlement rate. The calibrated model for zone 29 showed that soil behavior differed between the canal area and aside of the canal area under different loading conditions. Within the canal area, there was a high volumetric strain with less effective stress, whereas aside of the canal area, the mean effective stress was high with less volumetric strain. This result in higher deformation in the canal area compared to aside of canal area. |
| Year | 2023 |
| 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) | Kuo-Chieh Chao |
| Examination Committee(s) | Avirut Puttiwongrak |
| Scholarship Donor(s) | Asian Institute of Technology Scholarship |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2023 |