Modified limited life geotecxtile (LLGs) made of natural fibers for soil erosion control and soil reinforcement | |
| Author | Suthasinee Artidteang |
| Call Number | AIT Diss. no.GE-12-02 |
| Subject(s) | Soil erosion Soils--Reinforcement Geotextiles |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering in Geotechnical and Earth Resources Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. GE-12-02 |
| Abstract | Natural fibers can be manufactured into woven geotextiles for various geotechnical engineering applications and generally classified as Limited Life Geotextiles (LLGs) due to their limited life time of less than 2 years. This study involved both laboratory and field tests involving water hyacinth and Kenaf LLGs consisting of 2 types namely: coated and non-coated with polyurethane. This study was focused on the behavior of full scale test embankment with silty sand backfill on soft ground reinforced with Kenaf limited life geotextiles (LLGs) and water hyacinth for soil erosion control as short term applications. Tensile strengths were investigated in the laboratory and indicated that the plain pattern of woven Kenaf LLGs was the most appropriate pattern due to its high tensile strength. Subsequently, a series of pullout tests and large scale direct shear tests were performed to investigate the interface parameter, Rinter, between the backfill soil and Kenaf LLGs and the interface parameter of 0.8 was obtained for subsequent analyses. Furthermore, Slide 5.0 software was used to analyze the stability of the embankment with Kenaf LLGs that indicated higher the factor of safety than without Kenaf LLGs. The full scale test embankment was constructed in the field using silty sand backfill materials reinforced with coated and non-coated woven Kenaf LLGs to evaluate the performance. Consequently, the embankment behavior was monitored concerning its surface and subsurface settlements, excess pore water pressures as well as deformations of reinforcements. Numerical simulation using PLAXIS FEM 2D and 3D softwares were carried out to study the behavior of a full scale test embankment reinforced with Kenaf LLGs on soft Bangkok Clay. FEM 2D method overestimated the observed settlements data while the FEM 3D predictions agreed with observed settlements due to the threedimensional geometrical loading of the embankment with length to width ratio (L/B) of 1.0. Thus, FEM 3D simulation captured the overall behavior of the Kenaf LLGs reinforced embankment with more reasonable agreement between the field observations and the predicted values compared to the FEM 2D simulation. The polyurethane coating did not affect the embankment behavior as its purpose is to extend the life of Kenaf LLGs. Consequently, the Kenaf LLGs can be applied for short term embankment reinforcement in order to improve the stability of embankment on soft clay immediately after construction. This research also included the study on the effectiveness of water hyacinth LLGs to control soil erosion in a representative slope at different conditions of tests. Accordingly, the permittivity and transmissivity tests were performed to measure the flow rates of water hyacinth LLGs. In addition, water hyacinths LLGs were installed at the embankment slope surface with and without vegetation. Two types of water hyacinth LLGs with opening sizes of 8x8 mm and 12x12 mm were utilized. Optimum reduction of the flow rates of the runoff and amounts of soil loss were found when combining Ruzi grasses with woven water hyacinth LLGs. Moreover, the bare soil covered with LLGs having 8x8 mm opening size reduced the amount of surface runoff more than the LLGs with 12x12 mm opening size. Furthermore, the coated water hyacinth LLGs can increase the lifetime of about 25 percent more than the noncoated LLGs. In summary, Kenaf LLGs can be applied for short term reinforcement of embankment on soft clay in order to improve its stability during and immediately after its construction while water hyacinth LLGs can be effectively for soil erosion control when combined with vegetation such as Ruzi grass. |
| Year | 2013 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. GE-12-02 |
| Type | Dissertation |
| 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) | Pham Huy Giao;Kunnawee Kanitpong;Tawatchai Tanchaisawat |
| Scholarship Donor(s) | Royal Thai Geovernment Fellowship |
| Degree | Thesis (Ph. D.) - Asian Institute of Technology, 2012 |