Interface shear strengths of different geosynthetics under dry and wet conditions and the stability analyses for Sa Kaeo landfill liners | |
| Author | Ing, Anna Sia Hung |
| Call Number | AIT Thesis no.GE-02-08 |
| Subject(s) | Geosysthetics Shear strength of soils Testing |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. GE-02-08 |
| Abstract | The present study presents details of a direct shear testing program undertaken to determine the liner system interface shear strength for Nonhazardous and Hazardous Landfills Project situated in Sa Kaeo Province, Thailand. The base lining system of the landfills involved contact surfaces between various geosynthetics including sheets of smooth HDPE geomembrane liner, geonet, geotextiles, geosynthetic clay liner, and between smooth HDPE geomembrane and the compacted clay liner. The critical interfaces were located between the geotextiles and the smooth geomembrane, the smooth geomembrane and the geosynthetic clay liner, and the smooth geomembrane liner and the compacted clay liner with the inte1face friction angles ranging from 6.5° to 10.5° and 6.5° to 9.5° in both dry and wet conditions, respectively. The residual shear stress for these interfaces were attained at displacement less than 4 mm. Furthermore, most of the interfaces exhibited linear shear strength failure envelopes for the normal stresses ranging from 150 kPa to 400 kPa. The inte1face shear strength parameters obtained from the laboratory were utilized in the liner stability analyses specifically regarding to the tensile loads induced to the geosynthetic components at the side slope with inclination of I.SH: 1 V. Three current state of the design practices, namely: the limit equilibrium method (LEM), the limit method (LM), and the simple composite column (SCC) approach were adopted in this study. Both the LEM and the LM, respectively, overestimated and underestimated the tensile loads in the geosynthetics due to the assumptions adopted in these methods. The SCC approach yielded satisfactory results and the displacement compatibility between the compressive and tensile components in the lining system were taken into account. The factor of safety for the geosynthetic components in the liner were found to be greater than 3.0 for both types of landfill. In addition, the foundation soil settlement and waste compressions occurring during the waste filling and at closure were also briefly discussed. The foundation soil settlements of the aforementioned landfills would not significantly affect the perf01mance of the leachate collection layer. The global stability analysis for the landfill with the waste slope inclination of 3H: 1 V yielded factor of safety greater than 1.5 for the refuse density less than 24 kN/m3 and the cohesion of the waste more than 10 kPa. Nonetheless, the estimation of the waste strength properties have to be carefully evaluated and the global stability of the landfill can be increased with the appropriated and systematic sequence of construction. Finally, reliable stability analyses were successfully performed in this study based on the interface strength parameters obtained from the laboratory direct shear test with site-specific condition. |
| Year | 2003 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. GE-02-08 |
| 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) | Bergado, Dennes T.; |
| Examination Committee(s) | Takemura, Jiro;Park, Kyung-Ho; |
| Scholarship Donor(s) | The Government of Japan; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2003. |