HYDRAULIC CONDUCTIVITY CHARACTERISTICS OF A FINE-GRAINED SOIL POTENTIAL FOR LANDFILL LINER APPLICATION

Abstract

Sanitary landfills (SLFs) are usually employed as final waste disposal facility to protect public health and the environment. As a result of rapid population growth and urbanization, there is currently a great demand to construct SLFs in the Philippines. The hydraulic conductivity characteristics of remolded samples of a locally abundant fine-grained soil compacted at different compaction energy level is investigated to determine the suitability of the soil as landfill liner material. The hydraulic conductivity of lining system is one very salient feature of the SLF to prevent contamination of nearby soil and water sources. The physical properties of the soil are determined through a series of laboratory tests which includes the grain-size distribution, specific gravity, Atterberg limits, soil classification, Cation Exchange Capacity (CEC), X-ray powder diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEMEDS). The falling head laboratory test was conducted to determine the saturated coefficient of hydraulic conductivity. A numerical model was formulated that can predict hydraulic conductivity as a function of the void ratio. The resulting coefficient of hydraulic conductivity ranges from 1.98 x 10-6to 1.0 x 10-7cm/sec meet the Philippine standard requirement. The soil being classified as clay loam can readily be used as top lining material. However, additional study on unconfined compressive strength and volumetric shrinkage among other parameters is recommended prior to use of the fine-grained soil as bottom lining material as soil amendment maybe necessary.