The environmental performance of waste disposal facilities lies in the correct design and construction of their liners. There are several liners design recommendations prepared by regulatory agencies. Typical liner design includes single liners and composite liners. Single liners are constructed by a layer of low hydraulic conductivity compacted soils with final thickness according to regulation’s requirement or by a geomembrane. Composite liners include in their design combination of compacted soil layers and geosynthetic layers with different function. Most common composite liners are built by a compacted soil layer and a geomembrane. Hydraulic performance of liners lies on their hydraulic conductivity and the amount of leakage due to geomembrane imperfections, while mechanical performance depends on soil internal friction angle and soil – geosynthetic interface strength. Liner stability against sliding is of uttermost importance in side slope liners. It is a common practice to mix local soils with different amount of expansive clays in order to reach the target value of hydraulic conductivity. Clay addition affects soil shear strength and soil – geosynthetic interface strength. This research analyzes the effect of clay addition in shear strength of geomembrane – compacted soil liner. Effects of amount of clay addition, shear velocity and moisture condition are explored by means of direct shear tests between soil samples and a high density polyethylene smooth geomembrane.
Menu