Evaluation of influence of vacuum preloading to nearby non-treated area for Bangkok soft clay | |
| Author | Atapattu, Shashika Indula Sachinthaka |
| Call Number | AIT Thesis no.GE-19-02 |
| Subject(s) | Vacuum technology Soil mechanics--Thailand--Bangkok Clay--Thailand--Bangkok |
| 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 | Vacuum preloading with prefabricated vertical drains (PVDs) to improve the soft ground has been one of the most popular ground improvement method in Bangkok. However, the horizontal deformations caused during vacuum preloading extent up to a considerable distance with a risk of damaging the nearby existing structures. Although the principles of vacuum preloading are well presented in the literature, there has been limited number of studies focused on the deformations of the nearby non-treated area. In this study, evaluation of the of the horizontal deformations caused during vacuum preloading work were done through finite element modelling. Based on the calibrated numerical model, Influence chart is proposed to obtain the influence distance (IDE) of vacuum preloading. PVD length is considered as the main factor which determines IDE. Influence chart is later validated using the results of case histories in Bangkok. New design technique of gradually reducing the PVD length towards the edge, showed a significant reduction of IDE. Effect of weathered clay layer on horizontal displacements was also investigated, and it is concluded that presence of low-stiff and high-permeable weathered clay layers at the top surface results in larger horizontal displacements. Stress deformation analysis of the slope situated next to the vacuum treated zone is also performed and it is shown that, use of vacuum preloading instead of conventional surcharge preloading considerable reduce the total stresses and horizontal deformations acting on the slope. And, use of half-spaced PVD zone to control the slope deformation has also prevented the occurrence of excessive deformations of the slope. Horizontal deformations of the nearby non-treated area are also examined through volumetric strains and is shown that, volumetric strains only occur near to the PVD and ground deformations far away from PVD occurs due to the undrain plastic flow. |
| Year | 2020 |
| 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) | Chao, Kuo-Chieh; |
| Examination Committee(s) | Pham Huy Giao;Suttisak Soralump; |
| Scholarship Donor(s) | His Majesty the King’s Scholarships (Thailand); |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2020 |