## 3 Results and Discussion
### Predicted Unsaturated Hydraulic Conductivity  
The unsaturated hydraulic conductivity was predicted by utilizing the established best fit curve of the WRC for the compacted specimens and the empirical model of [PERSON] et al. [34], shown in Equation (7). The predicted unsaturated hydraulic conductivity of CCL, CL, and CPCL are tabulated in Tables 9-11, respectively. Furthermore, the semi-log plots of the predicted unsaturated hydraulic conductivity and volumetric water content of CCL, CL, and CPCL are shown in Figures 23-25, respectively. Accuracy of the Predicted Unsaturated Hydraulic Conductivity  
While the WRC-based method provides a practical approach to predicting the unsaturated hydraulic conductivity, its applicability is most reliable for well-compacted soils. The  
Figure 23: Predicted unsaturated hydraulic conductivity of CCL. Figure 24: Predicted unsaturated hydraulic conductivity of CL. Figure 25: Predicted unsaturated hydraulic conductivity of CPCL. accuracy of the predicted unsaturated hydraulic conductivity in the study depends on the accuracy of the WRC established using the filter paper method. Although other studies, such as the study of [PERSON] et al. [51], utilized the filter paper method in establishing the WRC of well-compacted and cracked specimens, there are still some parameters that may be established to accurately predict the unsaturated hydraulic conductivity of cracked soils and the soil-water interaction of unsaturated soils. The approach used in this study represents a simplified model of the complex WRC and unsaturated hydraulic conductivity function, which did not account for the stress-induced volume changes; suction variations, such as total suction and osmotic suction; and the effect of hydraulic hysteresis, since determining the hysteresis of fine-grained soils is often difficult, as discussed by other studies, which includes the studies of [PERSON] et al. [52] and [PERSON] et al. [53]. [PERSON] et al. [52] discussed a study that showcased the importance of establishing the hysteresis of the WRC for eight different fine-grained soil samples, which inferred that soil mineralogy and particle size distribution have a large impact on the hysteresis of the WRC [52; 54]. Furthermore, according to [PERSON] et al. [52], the moisture content of cracked soils can rapidly change at very low suctions, which makes it difficult to establish the WRC. [PERSON] et al. [52; 55] also formulated a method to predict the WRC and unsaturated hydraulic conductivity of a cracked soil based on calculating the changes in the crack volume during the wetting and drying process, accounting for the increase in permeability due to the crack network, since the preferential flow path is an important factor to accurately quantify the amount of liquid that will pass through a cracked unsaturated soil layer. The primary advantage of the method used in the study is its accessibility and reduced cost compared to direct experimental techniques. By using empirical relationships derived from the WRC data, it enables engineers to make initial estimates of unsaturated hydraulic conductivity without requiring extensive laboratory equipment. While the simplifications mentioned make the model practical for initial estimations, it is important to recognize that a more rigorous approach incorporating these additional factors would improve the accuracy. Future research should explore advanced numerical modeling or laboratory validation to address these complexities. To improve its reliability, future works should incorporate direct experimental validation, particularly for soils subjected to environmental stresses, such as wet-dry cycles. Future research may also explore a bimodal WRC, which may offer a practical approach for predicting the soil-water interaction in cracked soil [52]. Changes in the pore size distribution as the specimen develops crack networks due to undergoing wet-dry cycles may also be considered to improve the model. According to [PERSON] et al.