## 3 Results and Discussion
### Water Retention Best Fit Curve
#### 3.2.1 Best Fit Curve of the Water Retention Curve for CCL and CL  
The computed fitting parameters and points in the WRC of CCL and CL at each wet-dry cycle are tabulated in Table 7. Using the fitting parameters, the best fit curve of the CCL and CL WRCs for each wet-dry cycle was plotted as shown in Figure 21.  
It can be observed in Figure 21 that the air entry value of CL is lower than the value for CCL. Thus, as the initial void ratio of the specimen increases, the air entry value increases. The air entry value is the matric suction that keeps the soil in a saturated state. Hence, an increase in suction beyond the air entry value results in a decrease in water in the pore structure, which is replaced by air. Therefore, a higher air entry value denotes that the soil can retain water better than specimens with a lower air entry value. According to [PERSON] and [PERSON] [49], as the pores in the soil structure decrease, the radius of curvature of the meniscus decreases. As a result, the suction required for air to enter the soil fabric increases. Hence, CCL has a better water-holding capacity than CL.  
Generally, the decrease in the initial void ratio results in an increase in the matric suction due to the reduction in the radius of the curvature of the meniscus. Thus, residual matric suction is also greater for specimens with a lower initial void ratio, such as CCL, compared to specimens with a higher initial void ratio, CL. The findings from the study of [PERSON] and [PERSON] [49] and [PERSON] and [PERSON] [39] corroborate the behavior of the air entry value and residual matric suction for specimens that vary in the initial void ratio, in which a lower initial void ratio yields a higher matric suction across the WRC.  
When the wet-dry cycle is considered, it can be observed that the air entry value decreases due to the intergranular pores produced through cyclic wetting and drying. According to [PERSON] et al. [42], the specimens with a higher initial void ratio had fewer changes in WRC morphology before and after the wet-dry cycles. The obtained WRC  
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**Specimen Type and Number of Cycles** & **CCL-1** & **CCL-2** & **CCL-3** & **CL-1** & **CL-2** & **CL-3** \\ \hline Slope at transition zone, \(S_{1}\) & 0.318 & 0.227 & 0.289 & 0.228 & 0.219 & 0.190 \\ Slope at residual zone, \(S_{2}\) & 0.066 & 0.068 & 0.065 & 0.070 & 0.067 & 0.061 \\ Fitting parameter, \(m\) & 4.475 & 4.425 & 4.326 & 6.066 & 5.198 & 6.499 \\ Fitting parameter, \(n\) & 0.686 & 0.489 & 0.620 & 0.436 & 0.387 & 0.381 \\ Fitting parameter, \(a\) (kPa) & 34,000 & 32,000 & 34,500 & 30,000 & 30,000 & 39,000 \\ Volumetric water content at inflection point, \(\theta_{i}\) & 0.217 & 0.220 & 0.226 & 0.180 & 0.228 & 0.160 \\ Saturated volumetric water content, \(\theta_{s}\) & 0.734 & 0.734 & 0.734 & 0.939 & 0.939 & 0.939 \\ Air entry value, \(\psi_{b}\) (kPa) & 804.81 & 174.11 & 602.61 & 14.07 & 17.00 & 3.10 \\ Residual volumetric water content, \(\theta_{r}\) & 0.066 & 0.086 & 0.072 & 0.076 & 0.094 & 0.071 \\ Residual matric suction, \(\psi_{r}\) (kPa) & 101,601 & 124,573 & 117,651 & 85,388 & 123,299 & 114,608 \\ \hline \end{tabular}
\end{table}
Table 7: Fitting parameters of the best fit curve of the WRC for CCL and CL.  
Figure 21: Best fit curves of the WRCs for CCL and CL.  
agrees with the findings of [PERSON] et al. [42] regarding the effect of the wet-dry cycle on the morphology of the WRC. In the study, CL had less changes in its WRC morphology for each wet-dry cycle compared to CCL. This denotes that the wet-dry cycles had less impact on the porosity of CL, the specimen with a higher initial void ratio.