Natural Fibers in Reinforcement and Erosion Control Applications with Limited Life Geosynthetics

Natural fiber was fabricated into woven geotextile called limited life geosynthetics (LLGs) used for ecological ground improvement purposes. This chapter focuses on the performance of two real-field applications of kenaf in soil reinforcement and water hyacinth in soil erosion control, respectively. Laboratory tests were performed to investigate interface strength properties of kenaf consisting of large-scale direct shear tests and pullout tests. The kenaf-reinforced embankment system was instrumented to monitor its behavior during and after construction and, thereby, evaluate its performance. The surface settlements, subsurface settlements, excess pore water pressures, and deformations of kenaf reinforcement were monitored and predicted. For soil erosion control purposes, water hyacinth was selected and investigated in the laboratory using index and hydraulic tests. A field soil erosion control test embankment was conducted to confirm the performance of water hyacinth with and without grass covering. From soil reinforcement application using kenaf, it was found that there was close agreement between the measured and predicted settlements as well as pore pressures. Higher deformations were observed in the middle portions of the reinforcements following the settlement pattern. In the case of soil erosion control by water hyacinth, the surface runoff was reduced when using water hyacinth cover combined with grass, which was further reduced with increasing growing periods. In the absence of grass, the smaller opening size has better erosion resistance than the larger opening size when runoff was similar for both opening sizes. It can be concluded that the kenaf LLGs’ natural fibers can be used for temporary reinforcement and the water hyacinth LLGs’ natural fibers combined with grass covering can be applied for erosion control of slopes.