Effects of incompetent inclusion on properties of rockfills for dam construction | |
| Author | Moet Moet Lwin |
| Call Number | AIT Thesis no.GE-06-01 |
| Subject(s) | DamsDesign and construction Rockfills |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geotechnical and Geoenvironmental Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-06-01 |
| Abstract | Nam Ngum Hydropower project is located approximately 93 km northeast of Vientiane, capital of Laos. Nam Ngum 2 CFRD was designed with particular regard to the use of as much incompetent siltstone from the excavations as possible and incorporation of this rock in less sensitive dam zones to reduce construction time and costs. This study was conducted to investigate the characteristics of shear strength and compressibility on various blended proportion of sandstone and siltstone rockfill. Isotropically consolidated drained triaxial tests (100 mm diameter & 200 mm height) were done, 20 tests of dry specimens and 20 tests of wet specimens to investigate the influences of confining stress, incompetent rock content and wetting. Specimens were subjected to a range of confining pressures (0.3 MPa to 1.2 MPa) applicable to the dams of high heights. The study results discovered that MohrCoulomb failure envelope for this rockfill is markedly, which leads to reduction in friction angle with increase in confining pressures. The influence of particle breakage on shear strength of rockfill was investigated and maximum value of particle breakage coefficient was found to be 36.4% on dry tests and 44.5% on wet tests. The second part consists of 10 oedometer compression tests using the same gradation and percent of siltstone inclusion as in triaxial tests. The specimens (diameter. 150 mm & 100 mm height) were performed under dry and wet conditions. Five specimens were tested for each condition and applied the vertical pressure up to 2 MPa and the elapsed time was 6 hours. Through all these triaxial and oedometer tests, the effect of stress level, the percent of incompetent rockfill, the wetting condition and the specimen size on the shear strength and compressibility of sandstone and siltstone were investigated. The results of large triaxial tests (300 mm diameter & 700 mm height) and large compression tests (300 diameter & 180 height), which were tested by China Institute of Water Resources and Hydropower Research (IWHR) were also compared and discussed |
| Year | 2006 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-06-01 |
| 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;Glawe, Ulrich; |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2006 |