Investigation into the cracking potential of different composite liners under wetting-drying cycles

Abstract

The formation of cracks in compacted clay liners used as landfill liners creates a preferential pathway for water flow and pollutant transport, resulting in polluted soil and an increase in the hydraulic conductivity of the soil. The desiccation crack intensity in six variations in the materials of clay soil commonly used for landfill liner was studied using the wetting-drying cycle method and analyzed using crack intensity factor (CIF) values for 15 days with observations every 8 hours; the crack intensity was identified based on color sensitivity using MATLAB R2018b software. The results indicate that the more bentonite clay there is in the soil, the higher its CIF value becomes because bentonite has a high plasticity index. Adding lime and coconut fiber is associated with a lower CIF, and higher plastic and liquid limits are associated with higher CIF values. The CIF pattern identified in the soil variations (V1 to V6) shows that the highest CIF value is in V4 (4.11%), and the lowest CIF value is in V3 (0.0138%), with the reduction of CIF in two groups of clayey soils (A1 and A2) during the experiment was over A1 (10%) and A2 (16%). According to the results of this study, desiccation cracking testing on soil using the wetting-drying cycle method using CIF values analyzed ​​every 8 hours is promising for characterizing environmental conditions with accurate observations.