Settlement analyses by using numerical and analytical methods for embankments on soft ground in Hanoi - Hai Phong Expressway | |
| Author | Truong Quang Manh |
| Call Number | AIT Thesis no.GE-16-17 |
| Subject(s) | Numerical analysis--Vietnam--Hanoi Embankments--Vietnam--Hanoi |
| Note | A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Engineering in Geotechnical and Earth Resources Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-16-17 |
| Abstract | This paper presents the results of a comparison of ground improvement methods using analytical calculations and numerical analyses for Ha Noi – Hai Phong Expressway in Red River Delta, Vietnam. Ha Noi – Hai Ph ong Expressway connects Ha Noi Capital (one of two main economic centers in Vietnam) and Hai Phong city (the largest seaport in Northern Vietnam). The expressway was constructed approximately from 2009 to 2015. The soils where the expressway runs generally consisted of soft clay, sandy clay, sand or clay particles with plant residue. The blow counts obtained from the standard penetration tests that were performed at the site ranges from 1 to 7 for the soft clay. The groundwater level measured at the site ra nges from +0.97 to +1.63 m below the ground surface. Soil improvement methods including prefabricated vertical drains (PVDs) and sand drains were used to accelerate the dissipation of the excess pore water pressure within the subsoil due to the placement o f the highway embankment. The PVDs were installed with a spacing of 1.4 – 1.8 m and a length of 10 – 16 m depending on the thickness of the soft clay. The sand drains were constructed with a diameter of 0.4 m, a spacing of 1.8 – 2.5 m, and a length of 6.5 – 19 m. Monitoring instruments including settlement plates, piezometers, and inclinometers were installed and monitored during construction of the expressway. The settlement data were recorded from the beginning of construction to the time when approximate ly 90% of the consolidation degree of the soft ground has reached. The observed settlement ranges from 400 to 600 mm. The performance of the soft clay with the PVDs or the sand drains was evaluated in terms of settlement of the embankment using analytical calculations and numerical analyses. The analytical calculations were conducted using GI2000 program coded in FORTRAN 77. The numerical simulations were conducted using the Plaxis 2D software and the approach expressed by Hird et al., (1992) in order to model the vertical drains using 1 - D drainage element. The calculated settlement values using both of the methods were compared to the field measured settlement values. Besides, lateral movements and pore water p ressure w as analyzed using Plaxis 2D program. Since the excellent matching has been achieved, the correlation between soil properties from the field and laboratory tests is validated. Besides, sensitivity analyses are also performed to detect the critica l factor for consolidation settlement is the area. |
| Year | 2016 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-16-17 |
| 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) | Noppadol Phien - wej;Pham Huy Giao;Seah Tian Ho; |
| Scholarship Donor(s) | AITCV Silver Anniversary scholarship, Vietnam; |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2017 |