EFFECT OF MIXING METHOD OF MIXED PERMEABILITY CLAYSTONE AND BENTONITE

Abstract

In geotechnical work, soil permeability is one of the important parameters in the manufacture of landfill. Permeability is a geometrical property of the soil that shows the ability of the soil to deliver certain substances through its pores. Based on the PUPR ministerial regulation (2009), the bottom layer of the landfill must be watertight so that leachate is prevented from seeping into the ground and does not contaminate ground water. Many techniques can be used to prevent the spread of leachate into the groundwater table. One of them is the construction of a clay liner with regard to the permeability coefficient value of the clay barrier itself. This study aims to analyze the effect of different mixing methods on the permeability coefficient of a mixture of claystone and bentonite compacted at high density as one of the recommended materials as clay liners.

There are two mixing methods, namely (CS+AIR)+BN and (BN+AIR)+CS. Meanwhile, there are four kinds of mixed combinations based on bentonite content of 5%, 10%, 15%, and 20% based on dry weight with moisture content of 10%, 15%, and 20%. The sample was compacted to have a diameter of 6.34 cm and a height of 1 m with a dry volume weight of 1.8g/cm3. Samples were tested using the Falling Head Test method to obtain the coefficient of permeability.

Based on the research, it is recommended that the most ideal mixed method used forlayers clay liner in landfill is to use the mixed method (CS+AIR)+BN. In general, at a dry volume weight of 1.8 g/cm³, samples with a moisture content of 20% more produce a permeability that meets the requirements (that is, less than 1x10^-7cm/s) than samples with a moisture content of 10% and 15%. .

Keywords: Claystone, Clay Liner, Bentonite, Mineral Layer, Permeability Coefficient, High Density