| Author | Thet Lwin |
| Call Number | AIT Thesis no.GE-08-05 |
| Subject(s) | Rockfills
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geotechnical and Geoenv ironmental Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-08-05 |
| Abstract | This research was conducted to investigate the effect of small sized grains on the mechanical behavior of sandstone rockfill used in the dam construction for Nam Ngum Hydropower project, Laos. Isotropically consolidated drained triaxial tests on small specimens were conducted with the confining pressure of O.lMPa to 1.0MPa for dry and wet conditions. Four different gradations, varying with the different proportion of small grains content but the same maximum particle size, were used to investigate the influence of small sized grains on shear strength properties of tested rockfill. A total of 16 tests for saturated specimens and 12 tests for unsaturated specimens were performed. Results of small triaxial tests revealed that specimens with greater portions of small grains content give lower value of internal friction angle. Mohr column failure envelopes for both dry and wet specimens are non-linear. At high confining pressure, remarkable decreases in the frictional strength are observed due to the particle crushing. Friction angle (Oo) measured at the O3 of 1.0atm ranges from 53° to 55° for wet specimens and 58° to 59° for dry specimens. The specimens with higher dry unit weight (Yd) give the higher frictional strength, provided that the same maximum particle size and coefficient of uniformity (Cu) are applied. Furthermore, the effect of small sized grains on the compressibility of sandstone rockfill was investigated by conducting a series of small compression tests. The specimens were subjected to the vertical load with a range of O.2MPa to 3.2MPa, and the load increment ratio of 1 and duration of 6 hours were applied for each loading step. Well graded samples with higher percentage of small sized grains are more compressible than that of uniformly graded with lesser small grained content. In addition, the influence of compression behavior on the particle breakage of the specimens with the same gradation was discussed by comparing the changes in the gradation curves after one dimensional compression and triaxial compression. In order to find out the effect of gradations, dry unit weight and the specimen size on the engineering properties of the laboratory specimens, the test results of the present study were compared with the results of the previous studies done by IWHR & Meet (2007). |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-08-05 |
| 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) | Noppadol Phien-wej; |
| Examination Committee(s) | Bergado, Dennes T.;Park, Kyung-Ho; |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2009 |