Seepage control in earthen canals using alkali-activated geopolymer lining

Abstract

Earthen canals suffer from serious water loss due to seepage, directly impacting water transport efficiency. This problem is exacerbated by the increasing demand for water resources. Geopolymers can be used effectively to line the canals, reducing these losses. This study aims to examine the effects of new geopolymers on seepage in earthen canals. Fine ash-based geopolymers were chosen because fine ash is a byproduct of brick plants and is freely available in abundant quantities. Therefore, it can be considered a promising alternative to fly ash-based geopolymers. Literature lacks an integrated framework for permeability, lining geometry, and water level effects. The study included four parameters: permeability coefficient, lining layer thickness, lining orientation, and water level. To achieve the study objectives, a two-phase methodology was adopted. First, investigating the effect of fine-ash doses on soil permeability using laboratory testing. Second, using SEEP/W numerical simulation to explore seepage from an earthen canal lined with fine ash-based geopolymer under different doses. The results showed that the ratio of lining permeability to that of the original soil (KL/K) significantly affected seepage rates. KL/K ratios less than 0.05 achieved a very high reduction efficiency of about 85–95%, corresponding to 30% of activated fine ash. Lining orientation is an important factor. Full lining of the channel was the most effective configuration. However, partial lining with bottom and side linings yielded less efficient results, reducing losses by about 60% and 50%, respectively, compared with an unlined canal. This confirms that vertical seepage through the channel bottom is the primary loss mechanism. The result shows that increasing the thickness of the activated geopolymer liner significantly improved channel performance. These geopolymer liners reduced seepage by 70–90% in several cases, including one with a bottom-width-to-height water-level ratio of 6, although a positive relationship between water level and seepage remained evident. Using alkali-activated geopolymer in more than 15% of the dry soil effectively controlled canal seepage.